An unlikely review, but relevant nonetheless. Car snow shootout: 2011 BMW 135i M-sport wrapped in Dunlop Winter Sport 4D rubber, 17" snow whees. VS 2002 Toyota Highlander 4-cylinder, 4WD, with 15" snow wheels and Firestone Winterforce tires.
First off, the details. 135i M-sport is RWD, 50/50 weight distribution (as are all performance Bimmers) and is lowered, with the M-sport package dropping the ground clearance to around 5.25", 6MT short-throw shifter tranny. This is as dialed as most any RWD vehicle will be for winter travel; definitely not your grandad's RWD muscle car, with 70/30 weight distribution and a huge engine up front. The Highlander is a standard Toyota 4-cylinder, automatic, 4WD SUV. Plenty of ground clearance.
Testing conditions: dry, grippy snow over the past week, which turned to sloppy, nearly melting snow yesterday, then black ice last night. A good range of typical winter conditions for Central Oregon.
Acceleration performance: the 4WD Highlander can accelerate a bit than the BMW; it is 4WD, no surprise there. It will still slip on full gas out of 1st, so just step on the throttle lightly, and it gets rolling without a fuss. The BMW tends to slip just a tiny bit on slick surfaces, only in 1st and sometimes 2nd. Not bad, just a little wheel spin before it engages. The DSC does a wonderful job regulating power to the wheels: you feel the wheel's lack of traction, but it never pulls you out of line, as the DSC minimizes power to the slipping wheel. Keep the RPM's and torque low, and you have no problem getting started on slick roads. 6MT is a huge + here. Push RPM's up, and things might get interesting. Advantage: Toyota, but really only for inexperienced drivers.
Braking performance: the Toyota wears the more aggressive tire, as the Bimmer's Dunlop 4D is technically a "performance winter tire", in effect a bridge between an all-season and full studless. I went this route because we get plenty of dry, warm winter days, and I didn't want to lose all performance on my "fun" car. Even with the less aggressive tire on the BMW, it easily gets better braking marks. This is probably due to being able to manage speed through shifting much easier, and also the lighter weight of the car. I was amazed at how well it stops, while the Toyota tends to carry more speed into braking situations and wants to pack up sooner. I can see why many SUV drivers get over-confident and into accidents: a heavy car simply won't stop that quickly, and SUV's are heavy, even with good tires. Advantage: BMW.
Straight line driving at highway speeds: once at speed, the Bimmer tracks very well, far superior to the Toyota.
Snow clearance: I had the Bimmer in up to 6" of new, and it was fine. Over that, you are going to be plowing. If it is dumping at the hill and you expect a foot during the day, take the SUV. Advantage: Toyota.
Cornering: This is perhaps the biggest difference in the test. The BMW slaughters the Toyota. Cornering and braking are the most problematic parts of winter driving. We have a couple of shady, very slick roundabouts down the hill from my house, and taking these in the Toyota is pretty scary: the car hits the black ice, and immediately drifts toward the outside of the roundabout. You need to give the car some gas to keep the wheels moving and tracking; very unnerving. Same thing in slick corners in general; not a lot of confidence in this tall, heavy car. Tires want to break loose constantly. In slick conditions, I wasn't a fan. The BMW, in contrast, rules the corners. Weight distribution is perfect, and the same line that left you moving sideways in the Toyota will give you full traction in the Bimmer. Even giving it lots of gas coming through slick corners will result in very little rear wheel drift, and the drift you do get is predictable and easily corrected. The drift in the Toyota feels out of control, on the other hand; how I can I control it? The whole car is drifting, much tougher to counter-steer than in the BMW, which is at home when drifting. But, when cornering, it doesn't want to break loose, so you will have to either be trying, or be a dumb driver, to get into trouble. Winner: BMW by a landslide.
Conclusion: this test left me with more questions than answers. Why do people choose SUV's for winter travel? The handling of the lower center of gravity BMW was obviously superior to the Highlander. Of course, most people would prefer more clearance than a 135i M-sport provides, but a standard station wagon (assuming you are looking at SUV's for space reasons) such as Audi A4 Avant should be more than adequate, with 7.5 inches of ground clearance. I think the previous generation Outback has slightly more. The ultimate snow car would be a well balanced AWD wagon, not a tall AWD SUV, but I don't see many wagons. Weird. Is everyone just doing a bunch of 4x'ing on the weekends in their Honda Pilots and I am missing it?
Anyways, for the purposes of this test, the BMW is my preferred car on most snow days. If for some reason I could get stuck in deep snow, then it isn't an option, but for typical packed snow conditions, assuming you live on a plowed road, it felt like the safer, more predictable car than the Highlander.