Things I'm doing to get faster at autocross.
After frying the outside edges of my RE92's I purchased camber/caster plates. This helped my turn in and changed the wear pattern from the outside to the inside of the tires. I can get a much better autocross alignment now.
I purchased better tires, Falken Azinas 215-45 16, and they work great. I'm trying to get the one set to last all season. I will probably be showing cord by the end of the season. I run RE92's when not racing. I've also played with tire pressure a lot. On hot days I have good luck spraying my tires with water. This has helped me get faster with each run where before I would get slower with each run.
The rear sway bar made a huge difference in the WRX under steer problem. The STI motor and transmission mounts helped reduce the slop in the drive train and also smoothed the shifting out. I can reliably shift into first gear now. The throttle response is much better also.
For additional power I have an SIT up-pipe (no catalytic converter) and a Turboxs turbo back exhaust with a high flow cat. This really helped my bottom end torque and made my car sound like my old built up air-cooled VW motor.
Now I could be really really fast if I could upgrade the driver!
