Gotta think about what kind of shee you want to buy.
Do you want a relatively new one in stock form (a great idea if you are good at modding and want to build it up yourself) or if you want an older shee that's all modded out. If you are going to do a lot of snow riding this winter, which is what it sounds like, I would looke for a stock bike and do a couple things to it then wait for the summer to put the real mods.
Another strange but necessary question is if a Banshee is really what you want.
I mean, I don't know how much you know about atv's, but the shee isn't the friendliest snow/mud machine by any means.
If you're looking for a winter play toy, wouldn't you think a 4 stroke would push around easier?
If you're not looking to dog around on a 4 stroke and you are serious about shredding up the trails on one of these bitches, then I say you've made the right choice and should go out there and find your shee!