German Car Zone

Or as a CSL model of the upcomming M1... would that not be nice? A green car for political reasons and a real car for the fun of it. The chassis is there and now the engine. It would almost be strange if they would not do it...

Forget it.
The engine in the "25 Jahre M5" (called M5 CSL by some) is only a tuned version of the current V10, but it is 100% not coming into the F10 M5.
The whole car was just something for the engineers to play with, there was a big anniversary this year and so they got the chance to play a bit. Nothing more, nothing less. If you look at the "big" media, they often didn't mention the car at all. Only some message boards and "fan-sites" talked about it, it was never meant to be a big deal in the public, just a present from the M GmbH to the M5. It even has very unspectacular looks, standing next to a normal ring taxi you only see at a second glance that there are some things different, they even painted the carbon-fibre roof! Anyway, it is a nice car and sure as hell it is very fast, but it is not meant to get into the hands of any customer. It is just a demonstration of the M5 E60 "tuned to the max" in the style of BMW M, so with a lot more cornering power and still with an n/a engine - at least in this generation.