I put this kit (base TT02 with Impreza body) together a while ago and ran it a couple times in the basement with a cheap servo that I finally swapped out. I always had weird steering issues, but even with a newer Savox in there it still couldn't center properly. It centered fine after turning left, but after turning right it would go past center. I messed with tightness in all steering linkage, which is nearly impossible to remove anywhere near all the stiction in the steering. I ended up pulling the factory servo saver and popped in a high torque servo saver and it centers as it should now. My guess is the factory servo saver is too weak.... The steering friction really has me eyeing the aluminum upgrade.
Figured I'd post this in case it can help someone else thinking they've blown a servo, but just have a weak servo saver