Originally Posted by Dackelone
I would ask a place like Manhart Racing GmbH. They are the Meisters when it comes to transplants.
There was also that guy from Sweden(?) on 1Addicts who install a 1M engine in his e87, maybe he can be of help to you.
It was the e92 m3 motor and gearbox that was installed, in Germany someone also shoehorned in the s85 from the e60 m5. The best option would be a new clutch and a SSK IMHO. Unless you want to do the full drivetrain swap it isn't plausible.