First, I've been thru many loud pipe bikes (still have a couple) and the thrill is gone. I do mostly two up touring now. I live in a quiet neighborhood and have a long hill to climb to my house. Even when I'm trying to be quiet, most pipes will set off every car alarm on the way up. Not very cool late at night!
Understood, however, what I found interesting was an increase of +10.5 hp and +6.5 ft.lbs. torque with the intake alone and stock pipes. Adding the SPO pipes only increased the numbers by an additional +.5 hp and .11 ft.lbs. torque. The pipes didn't seem to make any appreciable difference in their test.
I havent used the pipes but i will second Gliders reccommending of M&M i have bought a few things from them