When i purchased my SG it had slip on V&H slash cut classics , so i thought well i would put on a set of true duals.After i installed the true duals I noticed a lil power loss.I had my bike on the dyno prior to the pipes after a few different tunes i found one that was well acceptable but not as good as the dynoed tune with my stock header.After finding the closest tune I love the sound but still a lil slower i think then stock headered pipe.I have a Power commander installed aswell as a auto tune system with a street sleeper K&N air intake on.My 250 watt 7.25 rokkers with a hogtunes amp is just loud enough to still hear the radio well at hiway speed.