Pretty sure it'd fit with stock drivers, but smaller drivers might be the way to go. That makes for a big change in final drive ratio. The gear down with 7t drivers has a lot of advantages, but it might be too much, and you'd probably need clutching adjustments. Keep in mind, it might still tend to rub the top of the tunnel more. You could also run the original drivers and trim the lugs. The bigger drivers on the Pro do give you an advantage in rolling resistance: the wider bend the track makes results in less parasitic losses. What I've got on mine is a Challenger Extreme 2.5 with the outer lugs trimmed down 1/4". Seems to work well, but I bought it that way, so I can't compare it to anything. Even though I can't speak from personal experience, what I've gathered from reports here and talking to people who know a lot more about this stuff from me is that about the only real advantages of the 2.6 over the CE 2.5 are less weight and slightly better performance in deep powder. Meanwhile, the CE works better in crusty or set up snow, and is a lot tougher. Don't get me wrong, the 2.6 is a good track (I have rode a couple sleds with that track), it's just that it's hard to get a good deal on one, and I'm not sure you'd ever see an advantage using it on a Pro because of the clearance issues. My thought is that it'll work, and might work well with a driver change, but may not be the best choice. Unless you score a great deal, it's likely to be significantly more money for not much more performance compared to the other options.
