I have a dark grey interior, but I've been amazed what a difference *dark tinted windows* has had on preventing interior heat.
Even with 109-111 degree heat in direct sunlight, the interior surfaces stay so much cooler without direct sunlight blasting them.
Yeah, I'm sure that is true. I haven't investigated aftermarket tints. We have some legal restrictions here in MA concerning the darkness of tints on the driver's and passenger's windows.