In my BMW e36 the LSD changes the RPM at cruising. So lets say I'm doing about highway speeds, without the LSD in I would be doing about 3-3500rpm. With the LSD, in my car it is a 3.30 gear, which lowered my RPM at highway speeds from 3-3500rpm to 2-2500rpm. In the case of the MINI, if I were to put an LSD that was geared as a 3.30 the rpm at highway speed would be lowered. Differentials, have no effect on the transmission gearing.