you dont need sled specific but it completely depends what you want out of your trailer. is it simply for keeping road grime off of your machines? do you plan on hauling a SxS and need extra head room? do you want to be able to haul a car? do you plan on heating it to thaw thing out/have a place to get dressed or have a beer after a days ride? IMO get as big as you can afford. nothing worse than tripping over sleds trying to strap/unstrap them, no room for fuel/gear, packed so tight sleds are rubbing each other or the walls of the trailer etc. i chose to be able to have 5 162's easily strapped, plenty of room for fuel/gear, fully insulated, dual heaters, tv and have room to sit in the front and have a party with all 5 sleds still inside. also can haul 3 rzr's or two cars (both have been done). once you know exactly what you want out of it then you can shop, way harder to add/change down the road.