My wife rides a 2005 600 Classic w/M10. If you don't have the tuning guide for the M10, find one on the web or buy one. My wife's sled was real squirrely when we first bought it and it turned out that there was too much pressure on the front of the skid and very little at the back so it behaved like it had a very short wheelbase. Now that we have hers setup correctly it corners quite nicely, bites good and turns in well, and at higher speeds very easy to drift the back end around with more throttle. You might have to shorten the front limiter strap in order to put more weight on the skis, or, you may need to increase rear preload for your riding weight.
I did find that tuning the M10 without the guide was a bit confusing. The owner's manual has some information but it's not very complete.......