not sure how to vote. I have kept my M3, I am the original owner of a 2008 E90, but have since added a Cayman S, NSX, and Jeep Cherokee as a winter beater.
I would only sell the M3 for an Aston Martin V8 Vantage (6 speed only) R8, or another Porsche 911 4S/Turbo.
2008 M3 sedan, Interlagos Blue - sold
Current Cars - 2011 BMW 1M VO - 1996 Porsche 993 Turbo -1995 Acura NSX - 2007 Lotus Exige S - 2014 Mercedes CLA 45 AMG (daily driver) - 2014 Jeep Cherokee Limited (winter beater)