01 gt engine upgrades

Next week I am purchasing a 2001 grand prix special edition gt coupe. I will be making several engine upgrades fairly quickly seeing as I have already saved the money. I have researched and I have come across a WIZAIRED airbox, K&N Cold Air System, Secret Weapon Cold Air Intake, Speedbuilt Fenderwell Intake, and SLP Cold Air Inudction System. Which is the best, is there another I dont know about? Which one brings best results?

Also I will be upgrading my PCM. I need to know out of the ZZP 1.0 PCM (89.99), Digital Horsepower PCM from PFYC.com (99.00), or the INTENSE PCM (99.99), which is best, and if they require premium fuel.

Throttle body spacers, There are many avialable, some create a .5" gap, some .75", and others a 1". Which is best? Is there a specific brand I should look for?

And finally...I want to replace the stock mufflers with something a little more aggressive and free flowing, but still keeps low interior resonance. I do not want the sound to overpower such that you cannot have a quiet ride with the windows up. If anyone has any ideas of just replacement mufflers which do the trick, let me know.

Thanks in advance!

How about just get the GTP and start out with the power your looking for. Not that expensive and cheap insurance....mine was 7k with 76 mlies on it....

well the GTP is actually more on insurance, the EATON supercharger practically needs to be rebuilt at 80k miles, and the GT I have chosen is a 2dr, with the special edition package, which is extremely nice looking.

I'm pretty sure the S/C doesnt need rebuilding after 80k.

my 2001 GTP was 81k miles. The supercharger is working perfectly fine.
I agree with jeegclwj, just look for a GTP couple. 2001 was the last year they made them. I extremely happy with mine.

http://www.costlessitems.com/parts/osc/index.php?cPath=47_48_70&sort=4a&page=2 This is probably one of the best on the market.