My cousin bought a trailor to haul around his racecar Camero that he planned on towing with his newly purchased Ford diesel dualie. He got a great deal on the trailor from another guy at the track and insisted I came over to check the new truck/trailor combo out.
The first thing I noticed was that the gate/ramp on it was only about 4 feet long. Given the trailor's platform was about 2' off the ground, that's a 6" per foot incline. The previous owner mostly used it to haul dirtbikes, 4 wheelers etc., and didn't have any issues.
My poor cousin didn't have a remote chance of loading that sucker. The front lip hit the ramp before the front wheels even touched it. He ended up paying 3-400$ and spending a lot of garage time building a ramp that folded and reached about 6-7' in length. He ended up being more proud of that ramp than the trailor.
Bottom line, as previously mentioned, make sure the obvious [brakes/lighting/etc.] are good and that a car as low as the NSX can actually get up on to it.