No issues in cold weather? How cold do you usually see it?
This will be the third sled that I have had this battery in and so far it's always started. It doesn't get real cold here though. I've only rode a couple of times where it got much below 0 degrees F.
I think the key with using a lithium battery in a sled, is to get one that has a higher CCA rating then a lead/acid battery to help compensate for the cold weather. That said, if I lived in an area where it got really cold consistently I probably would run the stock battery.