[src1995.sc]

Look for a 123d driveshaft. It is the twin turbo variant of the N47, and fitted with the 3L gearbox and diff, due to their strength, therefore the driveshaft should be the correct length between your gearbox mount and the rear subframe. You'll want to swap the whole e90 rear end over as the bolt spacing on the driveshafts and the rear hubs are different one the 3L and 123d compared to the 118d.

 

[src1995.sc]

Dropping a m57 in a 123d atm ...will let you know how long the rear end lasts

Interested to see how much needs doing, let us know how it goes