If you want the sound without paying a ton for it, do a muffler delete, and keep your stock resonator in place. All the shop will do is cut the pipe right behind the factory mufflers, weld a piece of pipe then weld the tips on of your choice. I went with the DC Sport dual tips which are sold at Advance Auto Parts, and aren't that expensive (helps being a Manager there with the discount and all lol), plus look great on these cars. Here is a video I did of the car idleing and then a slow take off then full throttle : http://www.youtube.com/watch?v=0MPxgON76Io
It sounds great at idle, normal acceleration, and def. at full throttle, but sounds like D**m helicopter when the AFM kicks in while cruising in 3-4 gears ... which is kinda cool the first few times you hear it lol. I get lots of compliments on how it sounds and the looks like "the hell is in that thing?" or "that's a weird looking GTO" lol. As for intakes, Make your own fenderwell intake, or just slap a 9 inch cone filter on the MAF tube till you can either buy one or make your own.