They have different rear anti-roll bars, never knew that. Yes I am bored, stuck on a train
e85M rear arb 21.5mm http://www.bmminiparts.com/DiagramView.aspx?DiagramId=79853&MOSP=49344
e86M rear arb 22.5mm http://www.bmminiparts.com/DiagramView.aspx?DiagramId=79853&MOSP=49422
eta I knew the dampers were different, and the springs were the same, but other than that I always thought they were identical, except the steering rack difference as well.

e85M rear arb 21.5mm http://www.bmminiparts.com/DiagramView.aspx?DiagramId=79853&MOSP=49344
e86M rear arb 22.5mm http://www.bmminiparts.com/DiagramView.aspx?DiagramId=79853&MOSP=49422
eta I knew the dampers were different, and the springs were the same, but other than that I always thought they were identical, except the steering rack difference as well.