I currently have the M200 rear without the lsd, and was trying to find the differences between the two with not much luck. So far all that I've been able to figure out is that they are both the same width and that the M220 has a lsd and the M200 does not, and if I'm not mistaken the M200 is a 29 spline. Hopefully someone can help me out here as I want to have some beefier axles, and possibly lockers. Thanks ya'll.