I went Dominator, but the dual can version. Shipped from Europe ~8/9 days. I went for Long Tubes with the collector fully under the bike.VCyclenut had a dyno run on the Dominator. A little quieter than the sound here, can also add a dB killer, but w/o is way great! Stainless is superb, fits perfect, the black carbon fiber second can is very nice as well. Another factor was Long Tubes (More Torque in cars anyway) with the collector fully under the bike. Those chinese ebay folded up shorty pipes are silly.
I have the M4 and love it. It’s deep enough and screams like a freakin panther at higher rpm’s. I have a couple different videos of it at idle/revs if you wanna see