Just wanted to see if anyone knows whether or not an e60 M5 diff is compatible with a non-M e60. I know the gearing is different, but is there anything else?

I checked into this a while back and decided no- unless you can get axles, hub, carrier, etc. This was not by actual trial, but research from REALOEM.com on the models- many different parts. Would love to find a $1500 or less LSD solution.

go with a quaife lsd...

Stupid question, because:

1) gearing is too high for us(3.62 - the M5 has the 7th gear)
2) there is the quaife option, that I chose for first here, that is simpler and cheaper. And absolutely plug and PLAY :)

1) The gearing for the 545/550 steptronic's is 3.38, so the difference is only ~120 rpm.

2) Used M5 diffs are $1.5k less than a new quaife. Not too shabby of a cost avoidance.

1) the difference is 5% on a already high 3.38.
2) used M5 diffs are free? Beucase a Quaife costs about $1500.

Not quite sure why you're stating an already high 3.38 as this is what BMW matched to the automatics. The automatics have different gearing from the manual and smg. All in all it would be the same change as what you did with your mod, a -7%.

The Quaife part itself is $1500 and to install it into the diff usually runs around $500.

I finally got an answer from a local BMW indy shop and they said the M5 diff is not compatible with the non-M. :thumbsdown:

where can you buy the quaife?

See the link below for a list of distributors. You can also go to www.diffsonline.com

Quaife BMW Distributors

HPAutowerks.com Group Buy