And after having a few cars with Huper Optik tint I can say, that ceramic film traps heat and radiates it like it's hot to the touch, but nothing else is in the car if you block the windshield. Having hot glass kinda sucks but it's better than having your seat melt your legs in the summer. Then in the winter, when you want some sun heat, you don't get it because the ceramic is doing its job of soaking up infrared.

I've seen some people stick with the factory tint on the rear windows and leave the fronts clear. Sometimes it's preference, sometimes it's state law. But I could do either after living with this arrangement for a few years. Ventilated/cooled seats are the business.