BMW has a strange history with its coupe versions of roadsters. The Z3 roadster got a coupe version in 1999, but it is generally considered to have been built by a renegade group within BMW. The coupe version of the Z4 obtained all proper corporate approval.
The Z4 M Coupe is very distinct from its roadster counterpart. The roofline, with its severely slanting back, changes the appearance dramatically from the convertible top. The front-end retains its muscular bulge.
There is little compromise in this sports car. For example, although it is a hatchback, it's strictly a two-seater in the grand tourer tradition, designed for two people to get away for a long weekend.