There's a Strosek style rear bumper that BW Motorsports sells that I'm seriously considering.
It has two horizontal slits that sits just above the two exhaust tip outlets. It's designed to vent heat generated by the exhaust/muffler out of the engine bay.
There's also a slit between the bumper and rear reflective lense for added ventilation.
Anyone have a pic of this on a car?
The only problem fitting this type of bumper is that it requires shortening of the bumper shocks