M7 will make 140 honest hp at sea level, but...only if the fuel is right. So check your plugs and wash...if it's rich, have dealer check fuel pressure. If it's high, buy an adjustable regulator mod and get it down to 42 psi. Check the oil injection ratio. Get it down to 40-1 if it is too high. If you are running lower altitude, I like the DnD y-pipe. Dynotech says it's good for 5 hp. Put a shift assist and orange spring in the secondary, and run a 36 or 38 deg. helix, or 42-36 NON progressive. Make sure you have the weight the chart says you should have for altitude, M7 will pull factory clutching in the primary if it is running right, and too light will kill trackspeed, more is better than less. Set belt deflection correctly and keep the sheeves clean. A fresh but broke in belt always seems to help, too. Aftermarket cans are problematic, most loose horsepower and/or cause a bog. I'm STILL running factory can in mine...always consistant. Throw off as much weight as you can afford. I love the float skid conversion from cat, better ride, less weight, reasonable price.
Word on the street is the powerclaw is the track to have. Also the '09 tail supposedly gets more chassis out of the snow and works better? No money for mods this year, still running a-20 in hillclimb, haven't run with any 2010's yet, but I kept up with the '09's last year on the trail and in deep snow.
Not saying you'll highmark any 8's, but these changes will help you keep up on the hill or trail in.
John