If you were cross shopping between a cayman S & an M3 because you needed a backseat then yeah I see your point.
a 3series over a cayman S? is this a late April fool?
Gee, I'm dying to get into the Cayman S now, except the fact that it costs about $200k new here.
IMO, the cayman S in the right hand will look 100 times better than any 3series you've seen.