Slip on and V band. If you're running big bore ex system on a lowered car and need to keep it tight to the floorpan, there are some places under the car which can be a bit tight so a slip on in that area. V band clamps are used where I have the room. I can go from a 4 silencer x pipe system, to open headers and any other mix 'n match combo. But I generally race with X pipe, bullet mufflers and pre axle turn downs since we have a 120db limit at the track.