I just put a Q4 on my '05 DRZ400SM and it rocks. Its 96db right out of the box and has a spark arrestor stock and looks very good on the bike. The 630 has two cans right? So if you have gone with a aftermarket can do you still have two cans or just one. The Q4 on the SM
Twin Arrows. Still havenĀ“t been able to find out how removing the cat changes the setup with the lamda off and the plug.
FMF has a Q4 for the 630 but I don't know if its one can or two. I guess I will have to call and ask.