HELP! e34 M50 -> M30 SWAP

[E30M30]

I have a 1990 535i wrecked and a 1992 525i with blown HG/disassembled engine.

How hard is the swap between the two since I have all the parts?

I loved the torque of my m30 so I'd prefer to use that engine, but we may be able to piece back together the entire m50 the previous owner took apart if it's really that bad..

[WatchMyDrift]

I think if the motor mounts line up it could be an easy swap.... manual or auto ?
I would expect you would have to use the cooling system for the m30.

[tfritz]

Only "difficult" part may be the wiring harness. My brother did this swap into his '92 525i, and because of year differences or something, he had to splice together the two harnesses which isn't necessarily hard, just very time consuming.

[E30M30]

Both manual. Can I just take one entire harness out and put the other in? I'd rather not splice.

[E30M30]

What year was your brothers 535i?