I am new to the site and a former 5.0 fox body owner now with a 2006 GT.  Obviously I want to start with exhaust and its been a while since I've had a mustang.  I'm thinking of a Flowmaster American Thunder axle-back kit for a sound I trust and price.  Anyone for or against this for the new style mustang or recommend anything different?  Also it looks like a simple bolt on install compared to my old cat back style which wasn't hard but sometimes annoying....is it?  Thanks  

Flowmasters sound great, I personally went with the Steeda Axleback exhaust.

The exhausts on the S197 is a lot easier to install, all except for that stupid clamp that connects the axleback to the midpipe. Ford did a great job on the exhaust so you won't gain a whole lot more than 10HP if you replace everything so my best advice is go with an axleback you like and get yourself a CAI with a tuner. The gains are very very nice with that setup. Check the following site for some more advice: www.southfloridastangs.net and look at the classifieds, I believe someone is selling their Flowmaster axleback with about 500 miles on it for cheap.

-Narsh