I'm having aluminum fuel tanks with a steel skid plate made for my universal. The rust in the fuel from the steel tanks bothers me. Make sure he mounts your jack far enough back that you can open your tailgate (if you happen to tow it with your truck), mine is not, and it's frustrating. I had him mount my 2 spares under the last trailer. The solar panel to keep the trailer charged is a great idea. On my next one, I'm going to have him install stronger tie-down spots on the side (the ones he puts on there are questionable). Ramping the wheel wells and making them match the track width of my car. Currently have one wheel on and one wheel off, so the car is always more on one side. I had him put scissors jacks on the back of my last one (you can load if not connected). I also always do my fuel on the non-camp side. I like to keep the camp side clear & I keep my generator on that side. Next trailer, I'll probably do a fuel reel in the front so you can fuel from either side.