I traded in my 08 M3 6MT with Navi with 16K miles on it.. Loved my BMW but wanted to get a 370z.. Have to say - I love my 370z!!! I do not miss my M3 as I love the looks of the interior and body design as well as the speed in the 370z. It helps that mine was fully loaded. 09 370z touring with Navi - White with Coil Overs, Greddy TiC Exhaust, 20's,and much more..
Plenty of power and not missing the M3... Not trying to knock the M3 - just saying not missing it with my 370z... Good luck!!!