Toadstool, I received my RB Pro Stock, installed it last evening, dropped off the bike to Gateway Bigdog today, they ran it on the dyno and after going up two jet sizes ended up with 108hp, 128tq. The previous dyno run with the V&H Big Radius exhaust 2 into 2 offered 100hp, 113tq. I had them dyno it exclusively for the sake of knowledge...I wanted to know the hard numbers following a 2:1 install and re-jet. In riding the bike up there today I notice the bike seemed to continue pulling into the R's as compared to the V&H, in addition, the motor does seem to spool up quicker.
An odd effect - and I may be hyper-sensitive to it's behavior now, but the motor feels as though it vibrates more. I questioned Tim on this (before todays dyno pull), he suggested it may require different jets to smooth it out.
Anyhow, end result following the RB pipe and re-jet, 8hp and 15tq gain...hope this helps someone in their decision process regarding RB Racing 2:1 exhaust.