So, I have had my B7100D for a while (10 months) and pretty much understand the B's as CUTs (compact utility tractors). I thought after a while I would understand the others better, but even after following the forum this year I am not picking up on the basic differences, primarily the L. I sense the M's are what I would call the full size tractors, ie, what I was used to on the farm. The BX's are the sub-compacts. What are the L's? Most that I see are 2WD and 2 cylinder, but higher horspower than some of the earlier 3 cylinder B's.