Doing something different is what created that problem... Do it like the factory engineers designed.
Slight segue: What about a side outlet, forward of the rear wheel?
That's just one reason not to dump the exhaust before the factory did. The other is that CO can collect underneath your Jeep and depending on conditions, it could make its way up into the passenger compartment. I'd have it extended out so it's at or close to where the factory put it.
I wonder if polyurethane bushings like those from Energy suspension would melt also.