First off, congrats on the 04+, welcome to the 7th gen club. Lol
180 tstat is only good if the engine is heavily modified and needs to stay cooler to prevent detonation.
K&N filter can be slapped on, but the best choice is a intake that can keep the filter from bouncing around. I made mine out of 3 inch PVC. Seems to work fine.
There's very little the GTP has to give up, the entire drivetrain as a whole won't work without a large amount of modification.
http://www.grandprixforums.net/threa...00-Powered-Car!!
That's 90% of the information you are looking for. You can keep some of the engine parts for a top swap, but you would need a Gen 5 supercharger. The Gen 3 supercharger on the GTP now would need modification of the PCV system in order to work.
The heads, valve covers, harmonic balancer, ignition coil bracket and tensioner with all of the bolts, studs and nuts, idler pulley and bracket, and possibly the injectors, can all be used for a top swap.
If you keep the 04 N/A for now, ZZP has a Front and rear PLOG if you want to spend the money, but headers will be needed, albeit more expensive, if you decide to add boost later.
For the trans, a TransGo shift kit will tighten up the shifts and make them feel more solid and snappy, but if you want the trans to hold up to more power, you will need hard parts and a good amount of money for those stronger parts.
A good tune will be what wakes up the car the most, ordering one from a company doesn't really give you what you want. There's a number of people on here with tuners, find somebody nearby and convince them to tune your car. That's the quickest way to get the most out of the car.
Suspension upgrades are also something you will want, cornering and braking sucks on stock GPs. Here's another link to read and learn yourself: http://getoverkilled.ca/wbodytech.html
Good luck with the GT.
