ive heard of a few ratios for e36 diffs . 2.79 , 2.93 ,3.25 ,3.64 ,3.73 ,3.91 and 4.1. usually the m series diffs are lower around the 3.25 mark. i had a 3.91 lsd on my cossie bmw and the acceleration was quite savage for a stage 3 also using a t5.