the day shrockworks makes a rear bumper for the 4 door is the day i buy a new rear bumper. I think it's funny that up until now the only thing available has been the double tube bumpers.
I think yours looks fine though. Anything is better than a stock rear 5LB steel job, like what i've got now, but i much prefer a shaped more square bumper, like the front shrockworks or ARB's.