I don't have any experience with PC for atv's but we've got them on our motorcycles and the performance gain is night and day. Plus the nice feature is once you buy the commander, you don't have to pay for updated maps. You can use all available maps at no additional cost. Not sure if any of you are in to tuning cars, but every time you want to change your map, you end up paying for it (unless you go with standalone engine management).
Perhaps a google search might pull of some people's experiences with PC on atv's
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