From what I could find online, the m6 Alpha weighed 466lbs dry, and that's an e-start only model. A 10% weight loss, or 46.6lbs, puts it at 419.4 lbs dry. If the new one is also e-start, that's pretty impressive. If not, it's still pretty good but most of the weight loss comes from elimination of e-start.
If you apply the 10% weight loss to the 800 at 446lbs with no e-start, you lose 44.6lbs, putting it at 401.4lbs which would make it the lightest mountain sled ever made, a pretty impressive feat for Cat.