[elhigh]

Of course there are limits - some municipalities police the window tint levels more aggressively than others. Others may not permit, for instance, reflective tint.

I've been reading about some metallic films that do a fantastic job of reflecting IR but the caveat there is they can seriously interfere with cellular reception. I've also seen mention of a so-called "ceramic" film - I would assume some kind of nanomaterial - that provides good IR rejection while still keeping the visible light transmitted - the number the po-po will be interested in - up in the acceptable levels.

I think the minimum light transmitted requirements don't apply to the back doors or rear window; obviously you would need to check up on that in your locale.