For what it's worth, I took my stock WRX on the Gandy Dancer when it was snowing with 2-3 inches of snow on it and had fun. It wasn't much for "off-roading" for me, as it was a straight shot of unpaved frozen trail, but my buddy who had a wrangler found some unintentional off-shoots and whipped around a few fields with his 22" wheels.
I just got a 2009 forester...its the base model. All stock. I would like to go on easy trails do some very mild off roading this summer. Any ideas?