I've had a couple people ask me hugh much power the exhaust makes. It does pretty well. We dyno tested this unit early on (last January) on a Mustang dyno. So don't get too taken at the peak numbers, its the curve that matters:
Before/After using Cobb OTS STGII we saw +22hp/+65 lbs peaks. Those were peaks but the curve looks very good. During most of the midrange your getting a +48hp gain. This is an OTS map, I'm sure there is more to be had with a good protune. This car was fully stock except for the Street series turboback.