I installed a winch on my enclosed trailer. It's rated for 3K lbs and pulls my 2.5K car on with no issues at all. Something a friend has done to his enclosed is to place some 2X4's on edge on the floor to guide the tires of his car as he loads it. This makes it easy to place the car in the same stop every time both front to rear and side to side. He does have a narrow trailer (Not 8.5 ft) so placement is important. With my wider trailer I just winch it on and just try to keep it mostly to one side so that I can open the driver door some if I have to. I usually only drive it off the trailer but winch it on.
