pretty much what all these guys said, i have a 2001 firebird w/Y87 package. all ive done so far is added a CAI (i recommend fast toys [complete] package, i bought the SLP one then found out theres an upgrade to it) i also bought a whisper air lid which made a LOAD of difference compared to the stock intake. if you cant do anything remove that air resovior/baffler thing in between the airbox and the MAF. just adding those three things made alotta difference. hoping to get an exhaust and do sum minor weight reduction soon.
also one other thing that no1 else mentioned but is kinda standard (hi flow airfilter)