Headlights on the Promaster are NOT very bright as it is.. Luckily I have the fog lights which seem to brighten up the road better then the headlights themselves! I wouldn't tint them myself no matter how "good" It may look..
I constantly see poeple tint their tail lights so dark you can't see them. I can't wait for someone to rear end them and then sue them for purposely rendering their brake lights useless. The headlights though? It used to be illegal to have anything but clear lenses over the headlights but I see a lot of new Fords with tinted lenses...don't know if they are factory or not. I wouldn't want anything that would reduce the brightness of my headlights.
Certainly not legal in Ontario. Given that tinting the headlights impairs your ability to see and be seen, and tinting the taillights impairs the ability of others to see you, it's not a wise thing to be doing.
If you want to do something like this, take the outer cover off and paint the part of the inside of the housing that is NOT part of the functional reflector around each bulb. Leave the outer cover clear. Of course, this is a lot of work.
There's probably a law that specifies how bright your headlights should be. I read somewhere online that the law for tail lights in my area specified they had to be visible from x feet away on a sunny day (or something to that effect). If you can look up the law, and comply, then what's the harm? Especially if you're upgrading the bulbs to offset the tint.
I also see idiots with tinted tail lights so dim I can barely see them, and I think it's dangerous and obnoxious. But if you're being smart about it, I don't see the big deal.
The problem is that if you tint the tail lights it renders the reflectors useless and that's what most poeple get tickets for. The reflectors must be seen at night from 1000 feet away with your high beams and 300 feet with low beams. It varies by state but manufacturers will always make them pass the most stringent state.