To answer the original question, here's a copy of a post I made back in '08:
I put one of those Northern dump kits on my '93 F-250. Was not at all unhappy with it, but wouldn't do it to my new pickup. I got a lot of use out of it, hauling dirt, mulch, firewood, and building demolition debris. Here's a few things i didn't like about it:
There's no provision to secure the front of the bed to the chassis. So, when unloaded, you could see the front of the bed bounce up and down as you drove. Never did any harm that I could tell, but i didn't like it.
I had hoped to be able to fill the two fuel tanks through the filler doors by locating the fill hoses just inboard of the body. The curved shape of the bed made this impractical, and I typically raised the body to fuel. (it was cool, though, to see the reactions of some people when the bed rose.)
The manufacturer provided a worthless piece of cable to support the cylinder/scissors mechanism from hitting the rear end when the bed was down. I fab'd a substanial support out of angle iron that was far superior.
They recommend you fabricate a bracket to weld the rear bumper support to the bed hinges. I was afraid if someone ran into the back bumper it'd screw things up, so I located the bumper lower and further forward so it could be attached directly to the frame and not interfere with the tailgate when the bed was raised.
I wasn't concerned about the insurance implications, although others here have been. It was still just a 3/4 ton pickup being used non-commercially.