Here is everything in a nutshell and I'm tired of reading this thread

1) Take off the 3.4" Pulley
2) Install a 180* T-Stat, if not done already
3) Install colder plugs if not done already
4) Get a Set of headers (they are what they are...you pay more for better fitment and coating materials...and yes a name brand.)
5) Get a PCM. ZZP = EPIC FAIL, do not go that route. Whoever does their tuning sucks ass. Go with a DHP, or Overkill. You can get a DHP from PFYC.com or 3800performance
6) Flowmasters = awesome. As long as you keep the resonator they are fine. No performance increases but the stock mufflers are the best muffs perf. wise anywhere.
7) SLP GTX is the Grand Prix that had a Ram Air Hood, 3.5" Pulley, SLP Catback, and Intake from the factory.

Hope this clears it all up.