there are a few different ratios available if you convert to the e30 medium case differential. the ti small case may have choices, but all I have seen listed are the 3.45 for the manual and something like 4.10 in the automatic. there is a supplier of differentials: diffsonline.com the website will show various ratios that are available. I have a 3.23 medium case, which was the same as the 95 m3-----at 70mph I turn 3000 rpm-----80 is about 3450. your engine swap will give you low end power for the numerically lower diff ratio, but the lower number will slightly affect your initial acceleration from a stop, so you want a balance between highway rpm's and strong acceleration to take advantage of the increased power. |