I am new to the form and just purchased a 2004 GM with 23,500 miles on it. My first question is, would I get the same performance out of a maurauder airbox or a CAI? 2. I am looking at a set of Cobra wheels and I'm not sure if they will fit right on or if i need spacers. And last, I am looking to upgrade the exhaust. Would it be better to purchase my mufflers of choice and have an exhaust shop bend the pipes vs. a bolt on exhaust? Thank you.