Get 2 stock sleds, get about 200 miles on them with the same tracks and see. After coming off an M1000 last year and going to an XP 800 this I'd be interested to see this in person. Power to weight lets see..
Box stock weights
M1000 (07 162) wet 619lbs 165hp (weights from wyoming T/A's wet weight thread)
xp 800 163 wet 535lbs 151hp
put a 200lb rider on each sled.
Cat 819/165=4.96 lbs/hp
Doo 735/151=4.86lbs/hp
I still think the M1000 would be the winner here, a lot more torque. Always fun to speculate though.