[FunkyStickman]

I just did some research on this myself, I've got a copy of the rules right here on my desk... hang on...

STX doesn't allow smaller supercharger pulleys, or upgraded intercooler/aftercoolers. Also, it doesn't allow bigger fuel injectors. Retuning is okay, using the stock computer. Headers/downpipes are okay as long as they're street legal. Strut bars and sway bars are fine.

DSP doesn't allow smaller supercharger pulleys. They DO allow intercooler upgrades, fuel injection upgrades, subframe braces, R-compound tires, and everything else that STX allows as well.

Basically, according to the rules, if you swap a smaller pulley on the car, and you're on street tires, you're automatically in SM (Street Mod) where you will get your @ss handed to you. If you're running race rubber, then you'll go into DP where you will still get your @ss handed to you.

My suggestion: If you want to be fair, buy a 3.4" pulley ring, and run in either STX or DSP. You might get away with injectors in STX if nobody contests you.