Correct about the bumper stains...

I run a HKS SSQ BOV and I love it... It does stain the bumper but I don't have any idle problems. Some people do, some people don't.

DON'T get an intake... Just take off the "snorkus". It will get you the same sound and you won't waste your money. You might even loose power going to an aftermarket intake without a tune...

As for exhaust I run a Blitz Nur Spec-R with an inexpensive bellmouth DP. It is LOUD but sounds AWESOME. Someone on here described it as sounding like "A dragon eating children" if i remember correctly. *FYI* it does set alarms off in parking lots at idle :-D

FOr engine management GO WITH COBB!!!! You WILL be happy. They have a new model out that has some neat features but if you're trying to stay in a budget just buy a used one, but make SURE it has been divorced from it's previous owners car...

You might wana go check out wrxatlanta.com for all of your wrx specific needs...

I've done TONS of research and reading so let me know if you have any questions...