You CAN use chains. The manual may recommend against, but I never had any problems. For those of us who live in apartments, and don't have room to store extra wheels/tires, chains are really the only option. But don't get cheapo chains, as they may have bits that stick out and can damage your car. Go to an auto parts store and look for some quality ones that are easy to put on and fit well. I highly recommend Laclede Alpine Series.
I was driving my '99 Outback Sport up to the ski slopes one winter. There was some slush and snow on the road, but there was NO chain advisory posted, so I didn't bother to put them on. About 2 miles short of the base, the road became fully covered in hard-pack snow and ice. I wasn't driving fast at all (maybe 25), and was going straight, but I must have hit a really slick patch, because the car suddenly started spinning to the right. We bounced off the snow bank and ended up facing back the way we came. It all happened in less than a second, and I came away with a $700 dent in my fender. My advice: Snow tires if you can afford/store them. Chains if you can't. Don't listen to anyone who tells you you don't need extra traction just because you have AWD.
Jordan