you can find a perfect fit, small case, 3.91 LSD at your local yard. Just gotta find an 85 318i. I found one on eBay from an unknowing seller w/supposedly 90k miles on it for $250 shipped. Upside of a slow economy = buyers market. Swapping to 205/50/15 tires yields almost same gearing as 4.10, but I might get a set of 215/50/15s, can't decide...