Yep, probably the tires. I had a set of Dunlop Winter Sport M3's that still look good, treadwise (1/2 gone). But, the traction really diminished to being worse than an all-season, so they were replaced.
I have General Altimax Arctics on my '12 and it goes very well. The TC light flashes a bit when you're just starting off, but it doesn't seem to kill the engine power dramatically. Alas, I can't disable that.