Throw most of your idea's out the window, your 2008 Grand Prix Base cannot be tuned.

Chips are a joke.

So basically you cant top swap your car or do anything major.

Only small stuff like a hv3, intake, those type of things. And if your going to change the exhaust just buy mufflers and have them welded up, save yourself the cash. Oh and yeah 3800's exhaust LOVE to drone with aftermarket mufflers, might not be kid friendly.