I was at the Ford show in Dearborn too! I didn't get to stay long as I took the girlfriend and it was hot and muggy (for her)... drag her to enough of these things and I was feeling sorry for her. (Me: oh, look at this one! Her: It looks the same as the last one. Me: Sigh)
The Steeda Streetfighter looked and sounded great. I'm not sure if it had any other exhaust mods besides the axle backs though.
On a side note, I really like the Steeda functional front fascia. It's on my wish list now.
2011 Black Mustang GT - Eibach Pro Kit - 275/40/19 Rears