I would check with Fast to see if the Polaris m-10 is the same as the Fast m-10. I have the fast m-10 and love it. When I needed some replacement parts I was looking for some used and the part numbers did not match and the measurements were different on the Polaris parts versus what I had. I stretched a 121 non metric to 136 and then 144 tipped up and needed to add idler shafts and such to help with track tension, slide wear and stability. If they are the same spend the money and get the mount kit from Fast as you need support in key spots and you need to cut away some of the factory reinforcements and put in new mounting plates. Good Luck!