This is a really easy question to answer. The company to do the work would have to be RML group out of England. Cost will be in excess of $500k.
Those are easy questions to answer because RML already did this engine transplant into the Nissan Juke. Supposedly you can now purchase for $590k US.
Tranplanting into a BMW would most likely prove harder because the electronics will be completely 100% foreign. At least the juke was also a Nissan. From the road coarse test done on fifth gear the Juke R is a complete turd to drive. I would have to assume a 1M transplant would be better than a Juke but not as good as the purpose built chassis designed by Nissan for the a VR38DETT.
If you have absolutely nothing in the world better to spend that kind of money on then so be it. I can think of dozens of production cars and many dozens of motor transplants I'd take before this though.