bmwe21.net forums

There is a very good summary of the engine options at Fritz's website here:
http://www.fritzsbits.co.uk/engines.htm

Jeroen wrote:That would be the most simple option then, by far. Welded diff is only useful if you use the car for drifting only. Regular track or road use calls out for a LSD. On the road I wouldn't go beyond 25%. These babies are rare but they are out there. May need a rebuild though.

Welders are fine for the road and track, I'm not getting into a debate but this is years of personal experience; commuting, track driving, Hill climbing, drift tracking etc. Touring cars had spool (fixed like a welder) in the late 80s! Not saying they're better but there not dangerous as people like to make out.

The problem i see with a welded diff is that one wheel is guaranteed to be travelling at the wrong speed when you're cornering. Seems like a grip limiting idea for road use, especially in the wet. fine for drifting, or loose surfaces though.

My m20b25 goes nicely, also having driven prakash's m50 the other day id go as far to say that i think mine feels abit quicker certainly more torquey although his is a standard engine mine has a pretty lairy 300deg cam tubular manifolds decent exhaust and a lightened flywheel, it all just needs setting up a bit and i need to look at the inlet side of things

But an LSD is a must i currently dont have one but the car is crying out for it im quite a hard driver and the open diff makes for very unpredictable cornering which gets a bit sketchy

Overall its a simple swap specially as you already have a 6cylinder in there

Hunting for an M20 now.
Thanks for the input guys...watch this space!