I just installed one. Sound is a deep rumble that isn't overly loud even when you crank on it. Pretty mellow pipe.
Haven't gotten it to a dyno yet so can't tell if there is a torque dip. Seat of the pants feels better in the low range than my previous true dual set up.
Thanks for the reply. They are redesigned from previous offerings. I know the early ones showed a torque dip similar to a Thunderheader, pretty sure it can't be felt in an appropriate gear.
Mine will be dynoed as soon as I can get some time away from work and set up an appointment. The early ones were made by Bub and since they switched manufacturers and did some redesigns in 09 I hear it performs better.