Having owned several bmw personally i would prefer to use the bmw gearbox for that engine as they are so smooth and reliable.
The only problem is they are considerably larger than a ford type 9. As people have already said it should fit but it will need alterations to the tunnel which will intrude on interior space.
I originally wanted to go down this route but i need as much space as poss in the car as im 6ft 4. Also didnt wanna have to figure out all that wiring and fit a cat.
But it will be possible with a bit of work and im sure there is enough knowledge and experience on this forum to help you through and obstacles you would come across.