You can get rail extensions and a 136" track for $500 or so and a tunnel extension kit for 200-300 new or ffind used stuff.Its pretty much all bolt in stuff and some riveting for the tunnel extension, be patient and it will go fine.If you did'nt like the rail extension idea you could just find a 136" skidframe, either way.Tracks Usa sells great rail extensions or you could also get all your stuff from Rich motorsports who is a supporter of this site.I run 1.25" lug ripsaw for my last couple tracks, no studs.I used to always run studs until this track came along, I think its great as is.I have not topped out my sled with this new setup, but I believe its just as fast as with the short track or very close anyways.I geared down one tooth on the top with a shorter chain also.Gas mileage is better too, that was a bit of a surprise.I live near Frederic and gassed up my sled at the B&B there yesterday afternoon, it was busy there!Lastly if you want an m-10 there pricey between 1200-1500 new unless you could find a good used one.If you went this route you'd probably have to stretch a 121" out to 136" with rail extensions which is what I did to mine and its great and very rugged so far.