The "M-Sport Line" and the limited availability of the M3 GT4 for entry level race teams I think are both great ideas: one to help the bottom line (which I have nothing against, the stronger BMW is financially, the more likely they will continue to produce an exceptional product) the other to help the enthusiast. The M-sport line I bet will do a great job of combining performance line parts with some M-tech visual aides to create a sharp looking and better performing car, all for a reasonable price with a warranty. For many every day people who may not spend half their life on these boards
they don't have the time or are not comfortable with mixing and matching performance parts and may not be sure what to get. BMW can combine some parts with their expertise to yield a better performing yet balanced package. The customer is happy, and BMW makes money, so its a win-win scenario.
As far as an //M diesel, I don't think it will ever happen. Though its frustrating to me how this country has no embraced clean-diesel technology. So many ignorant people just turn their nose up at diesels that burn less fuel, produce fewer emissions and are more likely to last 200k miles than hybrids, yet they run out to buy their hybrids because they are "in". If they introduce the diesel engines to the 5-series and 7-series lines, I will never buy anything but a diesel because to me a luxury car needs lots of torque, quiet and fuel efficient engine, and that is a diesel in a heartbeat. If I want high HP or insane performance I can buy an //m