Thanks for all of the info- this thread really helped. I'm a long time muscle car fan and am new to Ford. I just bought my first "toy"; a 2009 GT Coupe and absolutely love it! The 300 horses is great but, like any guy, I want to do some mods and boost its power. Exhaust is one mod I thought about doing (H or X now clarified- Thank you!), but being a newbie, I also want to add the most HP for the least amount of $... My thoughts were a cold air kit, exhaust, headers, short throw shifter, and a performance module... Any suggestions would be greatly appreciated!