Tim I get a lot of heat into the interior from in my C5Z. I believe they have a kit to insulate the interior better from the primary source of heat, the exhaust bundle right below the seats. It can get uncomfortably hot on occasion.
I hope that your issue is just exhaust and not something else. Any idea what kind of running gear temperatures you are seeing? Maybe that is not even possible to get I am not sure.
Good luck.