I would not sell a 2011 M3 to get into the 1M. Maybe if you had a 2008 and were looking for something a little different. I love the 1M coupe, but there's definitely not enough incentives to trade in a brand new M3 for one. Don't get sucked into all the "New M Car" hype. It's definitely well-deserved, but in no way does it make it a better car than the M3.
(1:40 @ Laguna Seca, 2:03 @ Thunderhill, 1:52 @ Infineon)