The rules regarding "no boost" mods, is just that... boost must be stock. Of course, some things effect boost, like a freer flowing exhaust, but that okay. You just can't up the boost with a boost controller. In fact there's still an issue with reflashes, in that it's very difficult to prove the map you have loaded isn't touching boost without having an independant datalogger attached to the car to record boost pressure.
At far as the STi in STU, I already see a huge issue on the horizon. Boost creep. You're not allowed to touch the turbo for porting, so adding that exhaust will mean you're gonna be creeping. 'Course everyone else in STU is gonna be bitching that the STi has a ton of boost, which it true as long as it's not blowing up the motor.
STU seems like a cool class, but this 1st year of it is going to be nuts. I know I wouldn't run it, because it'll be pretty expensive to build a car for the class and you're shooting at a moving target. It'd suck to buy some expensive parts only to have to take 'em off and sell them because a FastTrack comes out making it illegal. Which reminds me, I've got a hood scoop to take off.
