This probably has already been discussed many times over, but I didn't find an answer on search. Any horse power gains from adding a CAT back system? I just put on a Flowmaster 40 series which Y's out to dual tail pipes...

 

I have read dyno numbers for the Magnaflow (#15609 - which I just installed) that shows anywhere from 17 to 24 HP gain. Torque has very small gains but the key is that it doesn't lose any torque. I can say this though, it is much more responsive and can rip the tires off now...

Later,

Chris (ReelWork)

 

Flowmaster is not designed for performance, but it should give you a little more power than stock.