I recently had the front windows tinted at a shop. I researched window tint materials and not all products are equal. The cheaper products will turn blue-ish over time. The more expensive (by 3M and others) ones will not. I chose the most expensive tint, 3M Crystalline series:
http://multimedia.3m.com/mws/media/1161043O/3m-automotive-window-film-crystalline-series-brochure.pdf
This tint is designed to reduce the IR radiation (heat) without having to be dark. The front windows have CR70 and are barely darker than stock, but the tint supposedly reduces the total solar energy by 50%. The tint is expensive...around $100+(not including labor) just for the front windows. Hopefully this keeps the CHP off my back.