get the GMSTGII serpentine belt and drop a pulley to around 2.9
Get a dual pass setup and option B for bleeding the coolant.
Header 1.75 primaries at at least 2.5 outlet, 2.5" DP (3" if you can) 2.5" catback (so it doesnt get raspy)
a 3" intake, 08+SS/TC dampners and pedders springs.
2.8 pulley, 60# injectors = 250 bucks
hp tune from someone local = 150 bucks if its any more **** them
instant 250whp
catless downpipe = 200 bucks
should be at 260whp