I have this Classic rear bumper w/o the tire carrier:
I wanted a rear bumper of this general design that had a tow rating, so I went with this one. I have been completely satisfied with it so far. It has withstood rock bashing as well as towing my Voyager across town in an emergency (long story).
As for the installation, I didn't have to drop the gas tank... but I wasn't able to install the two inner braces. I was planning to drop my tank soon in order to replace the fuel level sending unit and
to upgrade my gas tank skid plate, so I waited and performed all three operations at once. Nothing like saving yourself some labor.
If you're just using it as a bumper, I suppose you could skip on installing those two remaining braces. But if you're gonna actually tow something, I highly recommend dropping the tank and installing them.