M&S does stand for mud and snow.

I saw the official winter tire recommendations in the Oct/Nov Christophorus. Seems that if I lived in Chicago I would go with these Ice and Snows. I went with the M&S for better dry road performance here in the Bay Area.

 

Last months Christophorus listed Porsche approved winter tire brands and sizes. Pirellis Ice and Snows were one of the choices. I've had to make some of the same choices between AS and Winter tires. The deciding factor was how much snow or how often I would drive the car in snowy conditions. AS typically gives better dry and wet handling but falls short in heavier snow falls 3" to 4" or when mixed with ice. Good luck.

 

From what I recall reading in Christophorus, there is an NO rated 255X55X18 Pirelli Ice and Snow that's 'V' rated. I haven't seen the 'V' version, and bought the 'H' one from Tirerack. I drove up to Tahoe today over ice and snow, and these tires worked very well -- much better than M+S on other SUV's that I've experienced. One thing I noticed is that MPG declined a couple with these tires / maybe it's the rubber compound, but it's definately a good tire for winter; smooth as silk, and no noise.

 

philg3--
How is the performance of these tires in the Bay Area?

 

Performance in Bay Area is very good -- virtually as good as the factory 18" Bridgestones that came on the original wheels. When I bought the Pirelli's, the guy at Tirerack thought that the 255/55/18 would be best with my mix of driving in snow (Tahoe) / non-snow (Bay Area); otherwise could have gone with the Dunlop 235/60/18 that optimized for snow. The Pirelli's were a bit cheaper -- about $150 ea + shipping $12ea + $150 mount/road force balance for set. Excellent set-up. Driving in the Bay Area, you would not even know you were driving on winter tires unless you looked. I also think that the rubber compound is better for the lower temperatures and for rain.

In April, I will switch back to my 20" set that has Continentals.

 

These are the winter tires approved by Porsche:

235/65 R17 108 H M+S (not for Cayenne S and Cayenne Turbo)
Continental 4x4 Winter Contact N0
Dunlop Grandtrek WT M2 (Rotation) N0

235/60 R18 107 H M+S (not for Cayenne Turbo with PK)
Dunlop Grandtrek WT M2 (Rotation) N0
Pirelli Scorpion Ice&Snow N0

255/55 R18 109 V M+S (not for Cayenne Turbo with PK)
Pirelli Scorpion Ice&Snow N0

255/50 R19 107 V M+S (only winter tire approved for the Cayenne Turbo with PK!)
Pirelli Scorpion Ice&Snow N0

 

Get the Pirelli. Outstanding preformance in snow

 

I originally bought 18" wheels for the snow but got a great deal on the 19's Since I already had the 19's on the CT I did not want to change the appearance of the car in the winter so I bough the Perelli Ice and Snow NO rated and have to admit they are a great snow tire. I feel little to no difference between the Rossos and the Ice and Snow in both dry and wet driving. No noticable road noise and although narrower by 20cm no less traction under tight conering. As with the bliazzacks and other snow tires that feel like snow tires causing oversteer and other traction issues under dry conditions, these are great. I do not know how they are in the snow as of yet, but I am sure they will do fine. $800 delivered to my door from Tire Rack.

 

Stay away from Bridgestone Turanzas M&S. These OEM tires are useless in snow & don't forget to turn off your PSM when the white stuff is surrounding you.

 

allright gents...thanks for the advice.Will go out and get a set of 18 inch or 19inch Pirellis. Almost bought a set or turbo rims with 3k miles on it with the Turanzas for 600 from a local guy but he backed out as the 20 inch snow tires he wanted to get were sold out and so he decided to keep the 18 inch.
BTW, drove in rains and slush last night and experienced a bit of hydroplanning as the tires I have (pirelli zero's) are slighty worn out.