There is no difference between the 08/09 and the 09/10 except the topsheet, however, between the 09/10 and the 10/11, they made it a bit more rigid underfoot, moved the butter-zones, and most importantly (and noticeable) is the addition of the Cap-Sidewall Construction, where there is a sidewall underfoot and cap construction on the rest of the ski, this will make the ski lighter and more durable, but still allow it to have the carve and edge hold of a sidewall ski.