[F360C]

I have the 3.91 ring and pinion ready to go so like you I have been trying to figure out what to do LSD wise.

Check out Racingdiffs.com as this are my current front runner. They offer a ZF 4 Clutch unit that seems to be pretty popular with the guys over in Europe. I know a couple guys over on M3 Forum are running them and they only had good things to say. They offer fully custom set ups and one option where you can easily change ramps but turning a screw. Even with all the install parts/shipping from the Europe it was still under $1600.

Originally I was going to just rebuild the OEM M Variable LSD with the parts Racingdiffs.com sells but after talking to him there was a change late in production of the diffs in our cars. Prior to this change you could rebuild them but after they changed the design slightly and now you can't rebuild them. This was confirmed by some guys over on the old M3forum.net. From what I remember this same new style M Variable LSD is the same one in the E9x M3. BTW the 3.85 Ring and pinion out of an E9X manual M3 can be used in our diff. Sometimes you can find a whole diff out of one of those for under $500 if someone is looking for a cheap gear set up grade over stock.

The only other option i am looking at is the OS Giken LSD and this is only because it is what Turner Motorsport ran in their E46/E92 Grand-AM cars. They say its the best and if it was their LSD of choice in professional racing then i think this says something. I have read some bad reviews but I wonder if it was due to install.