While I'm in there- rear end.

[shEck3lls0]

I am planning on replacing my diff soon with a 3.73lsd for my turbo build. I also need to replace my rear subframe bushings. What else should I do while I am in there and drop the whole subframe and diff down?

[ak-]

Prepare to have a useless 1st and 2nd gear lol.

[Holland]

3 clutch LSD.

[Wh33lhop]

3 clutch LSD.

3 or 4 clutch (use a Porsche clutch, they're a bit thinner and can fit).

You may want to get some weld-in adjusters or an adjustable subframe and do that while you're in there. That is, if you want better traction.

Check CSB and u joints
Trailing arm bushings
Diff bushing
Brake lines (chassis to subframe)

Depending on your power goals I also might consider revising your decision on a 3.73.

[shEck3lls0]

I am only planning on running around 10 psi, maybe 12 tops on an m42. So my whp goals are no more than 220.... for now. haha.

[GDA]

Weld in adjustable subframe for camber and toe
Weld in diff mount reinforcements on subframe
Rebuild driveshaft and drive axles

[Mr.SWISS]

Weld in adjustable subframe for camber and toe
Weld in diff mount reinforcements on subframe
Rebuild driveshaft and drive axles

That
And get this

http://www.ebay.com/itm/BMW-Rear-Bushing-Kit-E30-M3-325-325is-325e-318i-318is-Sub-Frame-Trailing-Arm-/120839083119?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item1c2292146f