I've been driving my 2006 G6 GT for about a year now, and I love it. Just a few things I would like to discuss. When I get back from my deployment, I plan on putting alot of money into my car. What are some ways I can boost speed and power, but also raise gas mileage? Would it be worth it to drop a GXP engine? Or would it be better to swap out parts here and there?