[allan]

what tires should I use for the summer vs snow?

 

[BenzFan]

Pirelli, Bridgestone and Michelin have a lot of good stuff.
I would recommend Bridgestone Blizzaks

 

[gtr]

I was thinking the all seasons run flats used on the regular CLA's. Who would want to change a flat tire in sub zero weather?

 

[brianch]

BridgeStone Blizzaks for winter (make sure the Blizzaks are up to the speed rating required by your CLA AMG - there are different versions of the Blizzak)

Michelin Pilot Super Sport for summer

That is my recommendation for your CLA AMG.