It uses the three bumper mounting holes in each framerail, same as the front bumper + 1 more. It does take some work to relocate the oil cooler higher and hoses away to clear up the real estate for the winch, and you have to make wires to relocate the winch solenoids, but the result is not too bad. The winch does not extend below the bottoms of the framerails.
The biggest drawback is the gear lever on the winch needs to be accessed from below. That is, you don't have to drop in the mud to do it, but you'll need to get familiar with using this lever without looking at it.