Not had any problems with my
MCS JCW as yet and I've quite enjoyed being in the snow with in places - I left a goon in Mitsubishi Shogun behind today who was faffing about like a proper idiot.
I'm considering the winter tyre thing as I know they will make a vast improvement and given the current conditions, they would be a good choice. In these ambient conditions with wet/icy roads and cold conditions, they will last very well. The killer for winter tyres are dry warm roads, then they give up.
Having said that, I don't have too many problems as I test vehicles for a living so hooning about on snow, ice and low grip surfaces is part of the sign off procedures I have to do for ABS systems and so on - so it's just "normal" for me.
I find turning off the stability control helps as I can drive the car, not the car trying to drive for me.
