The Subaru's all-wheel drive probably played a big part but these Pirellis are so far the best winter tires I've tried. Even better than Bridgestone Blizzaks that I've had on other Subarus, which themselves were excellent winter tires. The Pirellis have fantastic grip on packed snow and slush. The only time I experienced slight wheel spin was on glare ice. I also commend Tire Rack on their quickness of delivery. It usually took a few days on previous orders but this time I placed my order early afternoon one day and UPS delivered the following day. Can't get any better than that.