found this gear box on ebay... it looks like its 3 piece but i can't be sure. if it is i now realize there will be a bidding war over it.
http://cgi.ebay.com/ebaymotors/1975-BMW-2002-5-speed-245-Getrag-Transmission_W0QQcmdZViewItemQQcategoryZ33733QQihZ 007QQitemZ170199603356QQrdZ1QQsspagenameZWDVW

I believe it's an overdrive unit. Auction states it's out of a 320is. Interestingly enough, a sport 245/5 tranny out of a Jensen Healey just sold on ebat for $550, meeting the $500 reserve. No bell housing, but the front case (and input shaft, if needed) from a od 245/4 should be able to swap out easily. Makes me wonder what other cars may have used this box that may not have such a high demand as BMW's? Other than the seperate bell housing setup, the tranny was physically identical to a standard 320i 5-speed.
--dennis

Thats just a regular OD.

ah, ok.
hmmm something to look into. GOOGLE!!! it would be nice not to wait and wait for a transmission to come along that is closer ratio than a stock is and will cost a bundle.

though some of the jensen healeys were pretty mocked up. german tranny's, american engines, italian design, british wiring, french wheels.... yeap, a very british car haha.