I got 19s. 265/55/19 scorpion ice and snow. I got the oem 19 MB wheels form ebay. They were pretty much brand new (still had the sticker on the inside) and got the tires locally.
You can also do 275/55/19, 275/50/20, 265/60/18 for general sizes.
Like mine, the wheel arches will make the winter wheels "look" inset. Some people add a 30mm spacer to bring out the wheels to where the 21s are.
The Pirelli is a winter tire for "high performing SUVs" and recommended by MB.
Next time I may look for a more pure winter tire due to where I live, having said that, the pirelli are still a good winter tire and 100 times better than the 295/21. Those were like tabogins.
I am SOOOO happy...I bought some Bridgestone Blizzaks DM-V1s for my GL350 along with some Elbrus 105 wheels and a day later they have performed EXCEPTIONALLY well in our biggest snow storm in years! Thanks to Northern Performance, in Burlington, ON for an excellent price!! I basically paid only $19 more than if I ordered through Tire Rack!!
Being completely honest, I am surprised that they look fine...I too was worried that they would look like they were sunk too far into the vehicle. However, they look very good and I am happy that I got the 265s...they easily slice through the snow!