I have the Mtn. tamer rear suspension from timber sled for sale with fox floats. It also has 144" rails from ice age but stock rails can be used. I also have a 144'' with 1.75 lugs backcountry from camoplast that has a few tears but would still work on the trail apex sleds if you get a rail extension kit and want to increase your traction. The suspesion kit is a great thing for the mtn apex to reduce weight, increase traction and suspesion without sage. I have only assembled the the kit but has never been installed in a sled. Brand new the kit was $1700 but im guessing its not worth that now so looking for offers. I would recommend cheaking out www.timbersled.com and see what the product is all about. If intreseted on etheir the track or Mtn. tamer kit contact me at sheldongoodkey@gmail.com and i can also send some pictures of what i have.