+1 on the M3 steering feel. In normal it feels too light and boosted, in M mode, it feels too heavy - almost artificially weighted.
The M3 overall is very soft and cushy, not very involving to drive if you are used to fast nimble cars.
I drove the 911 Carrera S. I like the power of the 911 but the Cayman S feels much more balanced and tossable. The Porsches also have great steering feel which is lacking in the M3.