Very true that the 1M engine was borrowed from a non-M product. However, that would mean there is even a better chance that the engine in the M3/M4 will be special given how long the development time has been and the previous lessons learned from other BMW products. I haven't read any negative reviews of the 1M and it does seem to have a large fan base world wide. I believe turbocharging can work in an M product IMHO.