If you need chains, the snow is bad enough that you would probably become a snow plow no? I understand the M is capable in the snow, I drive mine in the snow. But if there is more than a few inches of snow, the M doesn't have the clearence especially in drifts or snowpiles that happen in intersections, parking lots, etc...
Let us know how the chains work!!
Here are a few plugs though:
http://www.m3post.com/forums/showthread.php?t=745549
http://www.m3post.com/forums/showthread.php?t=795297