I hope you didn't try to drive it with the summer tires. But I have been through 6 winters with my former SLK 320 and the new SLK 350. Never had any problems with it. But I DID make sure to put on the winter wheels and tires.
Don't know about the 55. Maybe just too much horse power?
Winter tires might have been cheaper than a new car...
I always drive my 55 during the winter and I've driven many other AMG's and BMW M's some considerably more powerful than a stock 55 during winter also, granted our winters are more mild (normally just cold and wet) with regard to what's thrown at us than some of you guys in the US season swing states suffer from but i suspect the weak link is the thing behind the wheel (no offense to you or your wife), i find some people just can't adapt to the granny mode that is required to drive a powerful car in bad weather.
I don't bother doing anything to the tires either, the standard fitment are basically year-round with an inclination toward summer, all i do is drive carefully being sure to make gentle steering movements and slowly getting onto the throttle and brake.
I've also driven my SLK in its modded form (500bhp+) during winter without issue.
Over the last few weeks the temps have ranged from -15C to -32C (add 5 - 10C for windchill) with about 20 cm (~ 8") of snow and a lovely pre-rush hour dusting each morning. My 55, with Blizzak LM-25 on stock wheels but 225's all around, takes it all in stride with any other RWD car.
Oh man. I had to mouth off about driving in the winter. Yesterday, I got stuck. Twice. The snow storm we had was really slippery snow. And it was 6 to 8 inches. I was doing fine until I parked in a parking lot. Went in the store a little while and when I came out, the snow had drifted to almost nothing directly in front of the car, but the rear had a fair amount of the 6 to 8 inches at least. I backed up and that was it. I think it bottomed out on the snow and it was so slippery even the winter tires couldn't get a grip. A stranger saw I was stuck and offered to help the wife push. Eventually got it out, but I was quite surprised.
On the road I seemed to have no more problems than anyone else was having. Then I got home and stuck it again as I tried to plow through the driveway. Got the car off the road so I could snow blow around it and then got it going.
To be honest, I think a lot of people had problems with this snow.
Proper winter tires are KEY when it comes to any amount of snow. I've driven powerful rwd vechicles (cars and trucks) for many years in the snow of long Canadian winters, and with a little common sense and real snow tires, it can be done.
One tip for those with the manual-shift capable automatic transmissions:
If you start out in 4, and turn off ESP when in snow, as well as stay in Comfort not Sport, you'll do fine in the snowy roads. Continue to drive in overdrive when you're at established speeds, and turn ESP back on once steady. My 2 cents.
As far as the AMG, stays in the garage!!