I can offer several helpful tips - I'm actually upgrading from a setup like you're talking about upgrading to.

First, saw your M-2 thread. Don't know much about the M-2s so I didn't chime in. Down at the bottom may have been a bottoming elastomer? I think my M-3s had something like that. Anyway, I have some M-3 elastomers I could send you. I think they would fit but I'm not sure. PM me if you want them.

As far as upgrading, a couple hurdles I came across when I upgraded from the M-3s. First, threaded forks are hard to come by. I ended up going to a high-end fork (couldn't stand the thought of adding two pounds to the bike vs. my ultralight M3s) that was threadless. At the same time I obviously had to get a headset and stem to go with them.

You have to make sure the forks at least have sockets for the brake bosses. If you have that you can get the bosses themselves at any bike shop.

Beyond that, all you need is a TravelAgent to make your old canti levers work with the v-brakes.

Chris