Short of expensive (or cheap and looks like butt) window tints, what options are there to keep the cabin temperature down when the car sits in the sun for a while? Rear louvers would be nice, but the only options on that for 4th gens look like they were made by Rubbermaid and still run on the pricey side. I've been temped to just find an auto shade to put on the rear window and use on an 'as necessary' sort of basis.