Originally Posted by ///M1
So far it has been speculated that it is just the end quad that is different on the 1///M, all else same as the 135i, so the aftermarket midpipe for $500 or thereabouts would give you some nice sound, modest gains, and weight reduction.
I don't know if that is true. Judging by the undercarriage shots from the Chicago Auto Show, the 1M looks like it will have much better flow than the 135i. I don't see any crush bends.