As for clear film, they do make several UV "films", they are not "tint", as they have almost no reduction in light transmission. The best film you can use on a car with the most heat reduction would be a ceramic-based UV film, such as Llumar's Air80, Suntek's 80% film, and a few other brands, I think 3M also has one, but can't find my 3M film book anywhere in my shop right now! These films have the highest heat rejection properties, and still has full UV rejection, but does not darken the windows. For the Air80 film, it looks almost identical to some of the Mercedes windows with the blue hue to their glass. Suntek's film has a green hue and isn't quite as clear as the Llumar film, but its also not nearly as expensive either.