Thought I'd share this, I waited for the pipes to get broken in before I made this short video, I think it sounds pretty gnarly (for a 6). In person it's a little louder than a GT with flows (sounds nothing like a GT, but it IS louder, slightly)
Idle is nice and smooth and with normal driving it doesn't attract the cops too much (even in Cali where it's illegal to have more than 4 cylinders and logical thought)
The specs are:
Exhaust: 2.5" pipes after the cats (stock cats), custom bends from cat to x pipe, and also from x pipe to tips. NO mufflers, 4 inch tips. The parts were under $100 shipped and the labor was $225 at the local 30 minute muffler.
S&B cold air intake
Tuner with custom tune (SF3) speed limiter removed, rev limiter at 6360rpm
3.73 gears and trac-loc from ford racing.
YouTube - exhaust broken in.mov
2008 4.0 SOLD (I will miss my first stang forever)
2011 5.0 black on black with 3.73 manual
and I still get over 26 mpg