I've got that kit installed on my Ranger. I've had it for roughly 4-5 years now.
I didn't really notice a loss in torque, although it was a while back that it was installed. The sound is really nice too, kind of throaty with a low rumble at idle. It is loud when you get on it, but not too loud if you don't rev it......best of both worlds. I have gotten complaintments for it quite a few times.
I'm kind of used to the sound now so I'm looking for something louder......I'm looking into a dumped flowmaster 40.
-Fabtech spindles - 35x12.5x15 BFG Allterrains - Series 97 Rockcrawler rims - E9000 Mile Marker winch (custom mounted) - Two 8" Prcomp 150 watt lights - Two 8" RF subs-Power windows and Locks - Bulldog alarm system - Custom rear bumper(not installed) - Plus More...