[Bc420i]

Is it possible, or would the engine block not fit the transmission. And what other complications would there be.

Is it just a stupid question?

[McLaren720s]

Even if it’s possible, It would cost so much that you’d be better off selling the car and getting an M4.

[PhizzurpF]

Originally Posted by Bc420i

Is it possible, or would the engine block not fit the transmission. And what other complications would there be.

Is it just a stupid question?

Why not just get an M?

[HighlandPete]

Originally Posted by McLaren720s

Even if it’s possible, It would cost so much that you’d be better off selling the car and getting an M4.

Unless it is the challenge… there will be a need for many upgrades. OP will need to study the specs for gearbox, etc., to identify the required mods and understand the weak links.

Takes me back to when mates were fitting Cortina GT engines/gearboxes into the 105E Anglia.

[Feddersen]

Biggest issue is probably that you will not be able to keep the xDrive. Then you need all the wiring, some ECUs, the transmission, the exhaust and the LSD. Probably also parts of the suspension and parts of the drive train and the brakes.

Will it work in the end? Maybe. It’s probably easier to buy a M3 and make it look like a 320i if you want a sleeper.

[Michael340i]

Yes it can be done, but would be extremely difficult, and would give you a car with negligible resale value.

As others have said, just buy a M4, then you get the transmission, suspension, brakes, seats, dashboard, and it all works together. Or tune your current engine if you just want more performance.

[bimmer456]

Originally Posted by Michael340i

Yes it can be done, but would be extremely difficult, and would give you a car with negligible resale value.

As others have said, just buy a M4, then you get the transmission, suspension, brakes, seats, dashboard, and it all works together. Or tune your current engine if you just want more performance.

I think he wants an x drive with more power so tuning is the best option. Or actually since it's a 420 maybe just get a 440ix and tune that. Engine swap just seems ridiculous lol. Not sure if it's a serious question or just a curiousty on the OP. Technically anything is possible. Tuned 440ix with bootmod or even jb4 would make more power than stock M4 and give you all wheel drive grip why would you want to swap an S55 and it costs way more if you could even do it. Or maybe tune a 435ix if on a budget.

[F30ZHP]

Why?