Ok here it is, a straight forward spring install with pictures. This should help pretty much anyone with an impreza sedan. These pictures and write up are on an 03 wrx sedan. I have lowered an 05 sedan and not much changed between the two body styles. So here it is.
Tools needed are as follows:
3/8" Mid or Deep 12mm socket
3/8" deep 17mm socket
3/8" impact gun (or substitute for a metric allen head socket set, and 17mm combo wrench)
1/2" impact gun (or substitute with a large 1/2" breaker bar)
19mm mid or deep 1/2" socket
19mm combo wrench
12mm combo wrench
Lift (or substitute for flat land, jack stands, and a jack)
The first thing I do is pull the car onto the rack and set the lift points (pinch weld spots on both sides, and front to back of car). I then open the hood and rear doors. I remove the rear seat, start with the butt cushion portion of the seat, remove the two 12mm bolts positioned on the vertical portion of the floor pan where the rear passengers calfs would be (see pictures). Then locate the 12 mm bolt located towards the middle of the seat cushion and remove it as well. Lift up on the front part of the seat cushion and remove from car. Locate the other three 12mm bolts holding the back portion of the rear seat, and remove them. Remove the back portion of the rear seat.
Locate the strut towers under the seat belt retractors. Remove the six (three per side) 12mm nuts that hold the strut in the strut tower. The one nut directly under the seat belt retractor will need to be removed with a 12mm wrench on both sides of the car, the other two should easily be removed with a 12mm deep socket and ratchet or 3/8" impact.
With those removed you can move to the front of the vehicle. Locate the strut towers under the hood, they will look similar to the rear (three 12mm nuts per side). My car is an early 03 so it has a bracket that share two of the strut studs on the passenger side, remove those two nuts and move the bracket out of your way. Go ahead and remove the six 12mm nuts (three per side) that hold the strut in the tower.
At this point go ahead and lift the car up safely I like to have all four wheels off the ground and off the car so it is one less thing I have to worry about. 19mm socket and impact gun (or breaker bar with vehicle still on the ground to loosten lug nuts) will take off the lug nuts. Remove the wheels and keep in same location, or rotate front to back.
I seem to start at the back first so locate the position of the brake line mounted to the strut. Take a flat tip screwdriver and a hammer from underneath to tap the clip off the bracket and remove brake line from strut. Repeat on the other side. Remove the two 19mm bolts and nuts holding the strut to the top of the knuckle. Use the 19mm socket and impact gun (or large breaker bar) with the 19mm wrench (use the open end of the wrench on the bottom bolts nut, if you dont it will get stuck between the bolt and axle boot when loose). CAREFULLY remove the strut from the wheel well. Repeat on opposite side of car. Take a strut assembly and use the spring compressor to compress the spring. Use the 3/8" impact and 17mm deep socket(or metric allen head to hold the strut rod while using a 17mm open end wrench to remove the nut from the strut rod) to take the top 17mm nut off the strut rod. That nut holds the whole strut assembly together. Carefully take each piece off the top of the strut and set aside in sequence for easy reinstallation. Release the tension put on the spring from the spring compressor. Remove rubber top cap from factory spring. Grab one of the rear springs from the box and install rubber cap. Install spring onto strut and compress spring. Re install strut top hat in opposite way you removed it. Re Install 17mm nut to top of strut and tighten til it stops. Make SURE that the arrow stamped on top points the same way that it did when you dissassembled the assembly. Repeat those steps for the other side strut assembly.
Go ahead and Re Install strut assemblies into the strut towers, then onto the knuckles. Make sure to also reconnect the brake line to the strut assembly and reinstall the clip.
Move ahead to the front of the vehicle remove the 12 mm bolt holding the brake line to the strut assembly. Next remove the 12mm bolt holding the abs speed sensor line to the strut assembly. Use the 19mm socket and wrench to remove the 2 bolts that hold the strut assembly to the front knuckle assembly. The top bolt is a CAM bolt used to adjust the camber from the factory. Carefully remove the strut assembly from the wheel well. At this point it is similar to the rear of the vehicle. Compress the spring carefully. Remove the 17mm strut rod nut, carefully remove the top of the strut remember and set aside every piece. UNcompress the spring, remove the spring from the strut, remove the spring cap and install on the new spring. Compress the new spring and reinstall all the parts to the strut top hat. DO NOT forget the metal washer . Reinstall the 17mm nut and tighten down. Go ahead and do the same on the other side strut assembly. Reinstall the strut into the strut tower assembly, then re install the cam bolt. It will only go in the side that it came out, one side of the strut is notched, the other is not. Make sure to aim the cam towards the top, you will want to get an alignment and the $25 per axle (front and then rear) camber correction bolts a couple weeks down the road(if needed). Make sure to reinstall the 12mm bolts for the abs line and brake line. Reinstall the wheels and tighten lug nuts. Lower vehicle to the ground, torgue lug nuts in star pattern. Tighten all twelve strut tower nuts. Reinstall bracket on passenger side strut tower (if applicable). Reinstall back portion of rear seat, reinstall cushion portion of rear seat. Clean up and enjoy the hard work!!!
I really hope this helps you guys. I have lowered well over 50 vehicles myself so if you need any help feel free to PM me. Make sure to look over the pictures as well.
Here they are, I am tryin to get them all in order