Last update: Sep 16 2018

2006 WRX Mods and Upgrades

DIY upgrades for the 2006/2007 Subaru Impreza WRX.

Hood Lift Struts

The hood prop normally attaches to the left hand radiator bracket when in the stored position. Rather than install the radiator bracket, I installed the Redline Tuning struts. The kit included pop rivets for the hood brackets. I used rivet nuts instead, to allow removing the bracket. Some rattle can paint matched the brackets to the car.

Hood lift struts Hood lift struts

Shift Boot and Knob

Red rally stripe knob, by SickSpeed. Leather shift boot and e-brake boot with red stitching from Redline Automotive Accessories.


Red Hazard Switch

Subaru part number 83037FE030. This switch came stock only with the 2007 STI Limited. Subaru made just 800 of those cars.


Intake Resonator Removal

Here is how to remove the intake resonator ("chamber" in Subaru speak).

  1. Remove the nut from between the input and output of the resonator, under the hood
  2. Remove the right front wheel
  3. Remove the clips holding the front of the inner fender liner until you can get your hands inside
  4. Reach up inside the fender and remove the lower resonator bolt

Resonator Resonator Resonator

Use Subaru part 46059FA000 to plug the input hole. Subaru leaves blocking the output hole as an exercise.

Resonator Resonator

Fog Lights

Fog lights Fog lights

Part NumberDescription
H4510FE030Fog Lamp Kit
H4518FE100WGFog Lamp Trim Kit, Aspen White
H4518FE100WUFog Lamp Trim Kit, Satin White Pearl
H4518FE100TGFog Lamp Trim Kit, Premium Silver Metallic
H4518FE100LRFog Lamp Trim Kit, Urban Grey Metallic
H4518FE100VWFog Lamp Trim Kit, Obsidian Black Pearl
H4518FE100DJFog Lamp Trim Kit, Newport Blue Pearl
H4518FE100BWFog Lamp Trim Kit, Aqua Blue Metallic
H4518FE100PGFog Lamp Trim Kit, WR Blue Mica
H4518FE100ROFog Lamp Trim Kit, Garnet Red Pearl

Yellow fog light covers from Lamin-x.

HD Radio

The Pioneer DEH-X5700HD keeps its memory when the power is removed which occurs frequently on a project car.

Pioneer DEH-X5700HD

Auto Dimming Mirror with Compass and Homelink

Mirror part number H501SAG100 fits Impreza 2002-2007. Mount adapter part number H501SSA040.

Mirror Mirror Instructions

2005 Tail Lights

The 2006-2007 Impreza tail lights are mostly chrome. Tail lights should be red. The 2005 tail lights are red, and are a direct fit. The 2005 tail light part numbers are 84201FE241 and 84201FE251.

2006 Subaru Impreza Tail Light 2005 Subaru Impreza Tail Light

Scoopless Hood

A hood from the non-turbo version of the car keeps rain off the electrics. The non-turbo car did not come in World Rally Blue, so this hood had to be painted.

2006 WR Blue Scoopless Hood

Center High Mounted Stop Lamp Delete

Although my WRX came from the factory without a wing, here is some information relevant to 2002-2007 WRX that do have a wing. The wing contains a third brake light (Center High Mounted Stop Lamp). Impreza without a wing have a third brake light inside the cabin on the rear shelf. Many WRX left the factory without a wing, except WRX STI and yellow painted WRX. Dealers added wings to many WRX that did not already have them and they left the existing third brake light on the rear shelf in place and connected. Those cars were sold with two third brake lights.

Impreza Center High Mounted Stop Lamp

To properly delete the redundant light, replace the rear shelf with part 65510FE100OE. This requires removing the:

Impreza Package Tray 65510FE010OE Impreza Package Tray 65510FE100OE

LED Lighting

Most lamps in the car were replaced with LEDs. The Philips Automotive Lighting Bulb Guide is helpful to identify the lamps. The headlamps were not replaced because significant modification of the fixtures would be needed to accommodate the LED headlights that are currently available.

In the image below, lamp A is a brake light, lamp B is a tail light and lamp C is a dual brightness lamp that is bright for braking and dim for tail light. The brightness of lamp A and C matches with brakes on, while lamp B and C match with brakes off. The designers used a trick to get the brightness levels to match. The incandescent lamp in location B is type 7443, which is a dual filament lamp even though this is a tail light only. The dim mode of lamp B is used to match the dim level of lamp C because they are exactly the same type of lamp. A dual brightness LED replacement is not required in position B.

Tail and Brake Light Lamps LED Tail Light LED Brake Light LED Brake and Tail Light

Here are the specific LEDs used in each location of the car.

Location Type LampsProduct CostAmps BeforeAmps AfterAmps Reduction
Fog H3 2 Calais H3-CAWDC $204.20 x 20.312 x 27.776
Brake (A) 7440 2 JLC 7440 7443 T20 Plasma $271.710 x 20.194 x 23.232
Tail (B) 7443 2 JDM ASTAR-7443-2835-33RED $150.425 x 20.126 x 20.598
Tail/Brake (C) 7443 2 JDM ASTAR-7443-3035-21R $201.710 x 20.328 x 22.764
License 2825 2 Zone Tech 8-SMD T10 W5W $100.322 x 20.040 x 20.564
Dome DE31751 JIANXIN-09-08-05-A04 $60.607 0.058 0.549
Trunk 168 1 Sylvania 168/194/2825 LEDriving $110.357 0.055 0.302
HVAC backlight 74 2 Generic eBay White $50.200 x 20.023 x 20.354
Glove box 74 1 SuperBrightLEDs 74-WWHP3 $20.200 0.012 0.188
Power socket 74 1 SuperBrightLEDs 74-RHP3 $20.139 0.012 0.127
Key switch 74 1 SuperBrightLEDs 74-RHP3 $20.139 0.012 0.127
Turn signal 7440 4 iBrightstar-7443-3014/3030-54/3Y $321.690 x 40.325 x 45.460
Front parking 168 2 SuperBrightLEDs WLED-W-120 $20.360 x 20.012 x 20.696
Front side marker 168 2 JDM ASTAR-T10-5730-6Y $100.360 x 20.106 x 20.508
Reverse 7440 2 iBrightstar-7443-3014/3030-54/3W $161.750 x 20.325 x 22.850

The total current reduction with the fog lights on is about 11A.

The electronic flasher module is a JIYE SG252B purchased on eBay. The SG252B flashes at a sluggish rate of 74 per minute. The OE electromechanical flasher rate is 84/m. I modified the SG252B by replacing the 10µF capacitor with an 8.2µF which increased the rate to 90/m.

Subaru Flasher JIYE SG252B JIYE SG252B

Steering Wheel Cover

The Custom Accessories 37000 steering wheel cover gives you the feeling of driving a Ferrari for just $6.

Steering Wheel Cover Steering Wheel Cover

Side Sill Spoilers

In its earlier days, this WRX was an unrefined, bare bones TR (Tuner Ready) without any fluff such as side spoilers. With a fancy new power plant, the car has graduated from knickerbockers to big boy trousers. Installing these items required drilling 10 holes along the sides of the sills. To figure those hole locations, I removed the side spoilers from a similar WRX and measured. The 12 holes underneath the sills existed already. They contained plastic plugs covered with undercoat. The side spoilers come in either the new curvy style or old straight style and in body color or black. I choose old black.

Parts needed:

Side Spoilers Side Spoilers

Red Badge of Amperage

The front and rear badges got decal overlays from Auto City Imports.

Impreza Badge Decal Impreza Badge Decal

Impreza Badge Decal Impreza Badge Decal

The steering wheel got one too.

Impreza Badge Impreza Badge

The badges next to the key lock were repainted with red accents instead of black and blue. To remove the badges, I heated them with a heat gun, then ran nylon line behind them with a sawing motion. To reapply, I used 3M heavy duty mounting tape.

Impreza Badge Impreza Badge Impreza Badge Impreza Badge

Fog Lights as Daytime Running Lights

The wiring is modified so that the fog lights can be turned on even when the headlights are turned off. This allows saving some power by using the LED fog lights as daytime running lights instead of the incandescent headlights. Normally when the headlight switch is off, the headlights are not off but merely dimmed by routing power through a power resistor (the DRL resistor). The resistor simply wastes some power so that the total used is the same as if the headlights were on at full brightness.

The first step is to unplug the DRL resistor. Now the headlights are either fully on or fully off. Then, reroute the wiring as shown in the diagram below. The basic idea is for power to come to the fog light relay coil from the parking switch instead of the high-beam relay. This way, the fog lights can be turned on when the headlight switch is in the first position. You can find detailed instructions on several Subaru forums. I did not ground the yellow-blue wire from the fog light switch. Grounding that wire allows the fog lights to remain on when the high beams are on.

Subaru Impreza Independent Fog Light Mod Subaru Impreza Independent Fog Light Mod Subaru Impreza Independent Fog Light Mod

WRX Pedals

Subaru WRX TR Pedal Mod Subaru WRX TR Pedal Mod

This 2006-2007 WRX TR came with plain black pedals. Upgrading the clutch, brake and dead pedals to the WRX style is easy. The accelerator is a bit more difficult.

The clutch and brake pedals have covers with a hard rubber lip. They can be pulled off and replaced with the WRX covers, part 36024FA010. These pedal covers are often sold in a set of three, along with the accelerator pad, part 36024FA001. This accelerator pad is intended for earlier model years and does not fit the 2006-2007 Impreza accelerator assembly.

Subaru WRX TR Pedal Mod

The 2006-2007 WRX STI accelerator assembly (part 36010FE040) fits the bill, almost. It is physically compatible and has the same electrical connector, but the connector pinout differs among the turbo, STI, and normally aspirated cars. The WRX TR stock accelerator assembly part number is 36010SA060.

Subaru WRX TR Pedal Mod Subaru WRX TR Pedal Mod

To get around the wiring mismatch, the connector and sensor can be moved from the old assembly to the new assembly. Thus, the original connector and sensor remain in the car. Note that the service manual advises "Accelerator pedal cannot be disassembled." It is held together by Torx head screws to discourage you. Nevertheless, disassembly is simple and the internals are straightforward.

Subaru WRX TR Pedal Mod Subaru WRX TR Pedal Mod

The new hybrid accelerator assembly produces slightly different voltages at the minimum and maximum positions. The difference is enough to require recalibrating the motor controller throttle input. If I were modifying the pedal in a gas car, I would recalibrate the ECU. Alteratively, the pedal stops could be trimmed or shimmed until the voltage range matches exactly.

PositionBeforeAfterDifference% of range

Subaru does not make a fancy dead pedal. There is an aftermarket dead pedal that looks very similar to the WRX pedals available from FastWRX. The rubber pads are attached with weak double stick tape. The small pads come off easily. The remedy is to pull them out, remove the tape, and glue them. The metal is very smooth. Scoring with an awl helps the glue adhere. Acetone removes residue left from the tape.

Subaru WRX TR Pedal Mod

Trunk Pouch

A pouch inside the trunk liner stows items that were previously in the spare tire well. The pouch is attached over the jack access cover with a snap kit.

Trunk Pouch Trunk Pouch Trunk Pouch

Defrost without A/C

Although this car does not currently have air conditioning, someday it might. When that day comes, the mod below will allow better control of the A/C compressor.

As with many cars, when you select a defrost setting, the A/C is engaged just as if you had pressed the A/C button (except the button is not illuminated). The reasoning behind this is that A/C not only cools but dehumidifies, providing maximum defogging. The mod below allows moderate defogging with heat alone. If dehumification is also needed, you can turn on the A/C by pressing the button.

Pop the shift lever cover loose to expose two screws at the base of the center bezel. Remove the two screws, then pop out the center bezel.

Defrost without A/C Defrost without A/C Defrost without A/C

Remove the radio. Unscrew the heater control assembly and tip it up to expose a limit switch at the bottom right.

Defrost without A/C Defrost without A/C Defrost without A/C

Unscrew the switch, pull it out and disconnect the wires with a soldering iron.

Defrost without A/C Defrost without A/C Defrost without A/C

Insulate the ends of the wires with electrical tape and reverse the removal process.

Defrost without A/C

Drivetrain Mounts

The stock drivetrain mounts and bushings are very soft and occasionally cause the car to buck upon takeoff. The problem was reduced with stiffer engine, transmission and differential mounts. I recorded video of the various parts of the drivetrain in action before and after each upgrade to determine the effect of each.

The pitch stop was upgraded to an aftermarket model, the NYPPD NY-SU-011. The video shows a modest reduction in the movement of the motor and transmission. There was no noticeable increase in noise.

Pitch Stop Pitch Stop 4 Stars

The transmission mount was swapped for the STI mount, Subaru part D1010FE020. This upgrade made a big reduction in the motor/transmission movement with little or no increase in noise.

Transmission Mount Transmission Mount 5 Stars

The transmission crossmember bushings were upgraded to the STI Bushing Kit, Subaru part B4100FG000. These bushings transmit a lot of transmission noise into the cabin. The noise level was a deal breaker. The original bushings went back.

Transmission Bushing Transmission Crossmember Bushings Transmission Crossmember Bushings 1 Stars

The differential carrier was steadied with the addition of the aftermarket Kartboy Rear Subframe Outrigger Bushings Comfort, part 1002-01-KBU-053-COMFY. These are not replacements but additions to the existing bushings. No instructions are included, leaving you with a puzzle. I found instructions here. Very good reduction in movement with little or no increase in noise.

Differential Carrier Differential Carrier Bushings 4 Stars

The engine mounts were replaced with STI engine mounts, parts D1010FE110 and D1010FE120. The video shows reduced motor movement. These mounts added very little noise.

Motor Mounts 4 Stars

The rear differential bushings were replaced with the Powerflex PFR69-122 black/race. With these bushings, the inside diameter of the center metal sleeve is too small and does not provide enough clearance for installation of the M12 bolts. The ID is 12.1mm (0.475in). The sleeves were replaced by headless drill bushings, increasing the hole to 14.3mm (9/16in). These Powerflex racing bushings provide excellent reduction in movement with little or no increase in noise.

Differential Mounting Bushing Differential Mounting Bushing Differential Mounting Bushing Differential Mounting Bushing 4 Stars


The rims are from a 2004 Impreza WRX STi. The rim size is 17x7.5, which is wider than the original 17x7. The tires are a quiet running summer tire, the Continental ExtremeContact DW XL 215/45ZR-17.

2004 Subaru Impreza WRX STi BBS Wheels 2004 Subaru Impreza WRX STi BBS Wheels

STI Mats

STI floor mats are a nice upgrade to the 2002-2007 Impreza carpet mats. The driver's mat has a reinforced pad at the wear spot. There is an extra bracket with a snap to hold the mat in position more securely. Part SCI440B202.

Subaru STI mats Subaru STI mats Subaru STI mats

The STI mats are a bit larger. This is evident when laying the WRX mats on top of the STI mats. The STI mats have a more precise shape that fits the contours of the car better, particularly in the rear.

Subaru STI mats Subaru STI mats

Sport Seats

The base trim level front seats were swapped out for the high-end sport seats. All the seats got new black covers from LeatherSeats.com. The door panels were also recovered, with red accents. The factory cloth is removed to install these seat covers. These covers are not leather, but vinyl. Replacing the seat covers was easy enough to do myself. The door panels were a bit trickier; I had an automotive upholstery shop do them.

Sport seats Sport seats