A BMW spokesman talking with
iMotorMag states that there is no business case for making an M Roadster/M Coupe based on the Z4 due to the poor economic climate.
However, the good news is that they do reveal that
BMW is planning an M Sport package which will include a body kit, large alloy wheels, tuned suspension and an M-branded steering wheel. In the cards is talk of an ECU remap upgrade to boost engine output of the 3.0-litre twin-turbo by an extra 20hp taking the total to 326hp.
BMW made similarly strong statements with the E85 Z4 as well but finally caved in after a few years of enthusiast demands -- so i'm not ruling it out personally....