okay, i've lived in new england for, well, let's just say more decades than i'd care to mention; and i've never owned a set of snow tires, believe it or not. but i want to put snows on the S55. i'm a tad confused and assume there might be others here way more educated in these matters than i. the stock setup is 18" tires, 245/45 up front and 265/40 rear. i know enough to know those are NOT common snow tire sizes . MB reccomends you buy new rear rims and go 245/45 all around. of course, they made that reccomendation when nobody made 265 snow tires. now somebody does (Bridgestone Blizzak LM-22 and Pirelli Winter 240 SnowSports - according to tirearck). so i have three options: (1) get a set of 245 rims and get the 245/45s all around. the most expensive option. this is what mb and tirerack suggest. (2) get a set of 245/45s all around and put the rears on the stock 265 rims. tirerack suggested this was doable, though it sounds like a bad idea to me. (3) get a pair of 245/45s for the front and a pair of 265/35s for the rear. #3 seems like the most rational alternative, with the caveat that the sidewall is 5mm shorter than the stock 40. what i would like to know is, how big a deal is this 5mm rear difference? the "airmatic" suspension has three user-selectable modes: regular, middle, and high where the latter two represent, each, a 10mm increase in ride height at standstill (the suspension lowers gradually with speed). so putting 35s on the rear and running the car at "middle" suspension mode results in, generally, the same height as running 45s on the rear - 5mm larger sidewalls than the stock 40 rears. any advice out there? with mbworld.org down for over a week now, i can't find a good source of help on this. tia, doody.