Yes, they can be converted. A good cyl can be picked up at salvadge yards for less than $400 usually for either. You will need the Front doors on both and in the case of the l you will need the front concave conversion grate as well. I have run the spike plate in the rear door on l's and M's with the spikes removed and I can't say that I really noticed any problems. The correct way however is to get the front grate kit if possible. I would get the bars wide spaced as well. Read 'bout this in posts way below if you are not familiar with wide spaced bars.