Depends on the kind of skiing you do. If you're talking cross-country skiing then it's a lot smarter to get a separate jacket for that because you have opposite requirements for standing around/walking and something as energetic as xc skiing.

If you're talking about downhill skiing you can do that in M65 no problem. I've used an M65 with a liner for snowboarding at -30C without any issues. It's heavier than snowboarding jackets and doesn't have a snow -skirt but other than that it was great.