Did some searching and found a couple of cars with swapped engines...
This is of course very professional done by AC Schnitzer... Must be a weapon this!!
0-100 km/h in 4.5 seconds and
80 to180 km/h in 7.9 seconds.
That's S E R I O U S L Y fast.
https://www.carscoops.com/2015/11/ac...-m50ds-engine/
Anyway it appears the engine bay on the F20 is pretty similar to the 3 series from the same period, and a 335D drivetrain would be a healthy and doable swap.
This guy did it too...
It'll be costly though, but what a sleeper it would be...