My lowered 4x4 truck will likely seldom see anything off road, much more then driving through my yard.

The lowest part of my truck sheet metal has 6" of ground clearance (the front nose piece). It also has full suspension travel. Its a 4x4 because it gets driven through out the winter, and around here that can mean through some pretty nasty roads.

I'm retired that means that if we get more then 6" of snow, I don't have to go anywhere, and most of the town would be shut down anyway. It has been used in almost 6" of snow and it works just fine.

Its lowered because I want to park it in my garage, and because I don't want to have to climb up into it, and because I like it that way and its my truck.

In order to stay on topic, lots of guys that use the Mustang tank in trucks mount them off angle iron brackets bolted to either the top flange of the frame, or the bottom frame flange. Bolting to the frame flange allows some space between the tank and the bed floor to run the fuel fill someplace other then up through the bed floor, and that also protects the top of the tank.