The difference between the C2 and M2 is pretty much the shock isolated bezel and the additional o-ring at the tailcap end of the body. Both parts can be bought by either contacting your trusted SF dealer or SureFire direct. To get the L5 all that is needed is the KL5 Luxeon bezel and the Z58 Clickie TailCap - these might be available as spare parts, not sure though.
Hope that helps a bit. /ubbthreads/images/graemlins/wink.gif
I felt like leaving a bit of work behind for you /ubbthreads/images/graemlins/poke2.gif /ubbthreads/images/graemlins/evilgrin07.gif /ubbthreads/images/graemlins/nana.gif