Which catback exhaust puts out the most horsepower

 

i my self don't know.
what i was going to do is just go to a local shop and have them make one the way i want.

 

catbacks for the xb i belive only magnaflow makes one and the rest are all axle backs

 

Borla has a dual catback, and Thermal R&D makes one thats a little harder to find.

Check this out, they have some good info and nice dynos as well...
http://www.tprmag.com/issue/18/18_xb.shtml

 

hands down..... you will not be unhappy with Thermal anything! AND, you will have clout with the turbo owned community.

 

that borla setup seems to be a real bad ___

by the dyno proof, if you want a single outlet go with the Thermal, but if you can muster the duel, go for the borla

 

Alternately, just buy an axleback that you like and have a muffler shop cut 2.25" piping to the cat for you...

A catback would require professional mounting anyway, so don't limit yourself to just catbacks (there are only a few available)