Im still new at this but would I need anything to else when combining exhaust (from the headers) and pcm such as smaller pulleys.......I have a 2004 gt2 and is not supercharged and also this doesnt void my warranty right?

I would guess any time you change computer settings that it would void your warranty...

agreed.

Federal law prohibits the dealer or the manufacturer to void your warranty when it comes to aftermarket parts. The act is called the Magnuson-Moss Warranty Act. See link below:

Click here (http://www.enjoythedrive.com/content/?id=8128)

However, if you take it into the dealer for a warranty repair and they find that the aftermarket mod caused the problem then you're SOL and will probably be charged. Regardless, they cannot void the entire warranty.

Thats good to know...