I believe 2000 and older is kick and electric.
I live in Arizona and will be riding year round..i haven't had it out in the summer yet but its such a small engine i doubt it will affect anything.
They are snappy because they are geared low..but don't expect the power to rip the bars out of your hands. They are a trail bike, not a motocross bike. Forget going fast over whoops..it doesn't work very well!