I have the Borla Catback, love it. Not sure if it's any better or worse than any other track exhaust. The Joe-Z has some proven tested numbers by members here. I refuse to put my car on a Dyno, sorry.
It was a pain in the ass to install, I had to go back to the shop twice and it had to be spot welded to the thingamajigger because it would get hot and start rattling. I could not tell you if this is due to a poor installer or poor quality control, but it sounds MUCH better than the stock exhaust. MUCH louder. Coupled with the K&N intake I would turn heads at 3000rpm, higher than that and it roars like no other.