I haven't tried it myself...yet (only because I haven't had any interest in "tinting" an RC, until now...but, I'm planning on trying a method others have reported works well. Note, in advance, that this requires using an airbrush.
Start by painting the body as you normally would, and then remove the window "stickers". Next, dilute black airbrush paint until it's as transparent as you can make it. You'll have to spray incredibly light coats on the interior side of the windows, just a few (2-4) passes at a time, and then let those parts dry for 15-30 minutes. Then, check your "tinting" to see if it's to the 'darkness' level you want. The thinner the latter of paint you can make on each pass, the better.
In the end, it'll probably take 6-10 passes, but you should achieve what you'll liking for. The first time attempting this (and, something I'll be following, myself), you should probably test it out on a spare piece of Lexan. I'll be using scrap pieces of Lexan, from cutting Lexan bodies for my off-road race vehicles (I knew I was saving them for a reason ..I just didn't know, initially, what that "reason" was).
As for headlights/taillights, you could probably do the exact same thing, albeit with different colors (ie. yellow & red). I don't see why it wouldn't work the same as tinting the windows .
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