I don't know what HP numbers I'm at, because I've never dyno'd it but I have a 1000cc Cutler motor in a M7 141 with the attack 20, just like you. It runs very very well, and yes it spins a lot on hardpack, but in deep fluffy powder it is awesome. If you want something that is good in all conditions, get a different track. If you want something that is AWESOME in deep fluffy powder, don't do a thing. I would never go to a longer track because I love having a light weight, easy to throw around, easy to sidehill, and great for jumping sled that climbs exceptionally well (compared to other N/A sleds) in deep powder (which is what I live to ride in). Yes, it spins like crazy on the hardpack (my track is in pow position), and at times can be a little scary in those conditions, but so what!! When it's hardpack, you can climb things you shouldn't anyways (even with the A20), and once you get used to it spinning and know what and what not to do in those situations, it's still a great set-up IMO. I bought my '05 M7 new, and after one season put the BB on it and have had it ever since. I've since done a lot more to the sled, but it is still 141" and still has the A20. ABSOLUTELY LOVE THE SLED AND SET-UP!!! It is perfect for what I like to do.