Drivetrain question

[The Humjet]

I have an e30 with an m40 engine
I want to swap an m20 with an eta bottom end with an added turbo.
i was also planning to but an LSD on sometime soon into my stock small case diff, with the 2.7 stroker being dropped in shortly after that can i keep the existing m40 gearbox and drivetrain or would i have to change it over to an m20 drivetrain.
What can I keep and what would I have to change?
Should i put the LSD on last?

[jlevie]

The best option would be to get a complete M20B27 power train (engine, transmission, drive shaft) and couple that with the limited slip diff of your choice.

[The Humjet]

So it doesn't matter if I use the stock diff but the driveshaft and gearbox must change

[MR 325]

Correct. Although the small case diff might not hold up in the long run.

[jlevie]

I'd certainly change the small case diff to the medium one from a 325e/es or 325i/is. Especially if you have plans for a turbo.

[The Humjet]

So basically the whole drivetrain needs to be changed over if I want it to last a while.
What other things should take into account When doing this conversion (cooling, ecu, etc.) is it's easier to just buy a 325i rather than go through all this trouble (btw a 325i down here in Australia costs about $8000 stock) or should work on the existing engine I have.