personally i wouldn't go with the black out look. cuts the light output way too much and really doesn't look all that great.
instead look at a set of smoked led tail lights or the car led ones that a few people have. i have a pair or the ebay smoked tails and they look great and are still functional.
thats just my .02 but do what you like.
The best way to do it is with a special black paint and clear coat mix. It pwns nightshade and it doesnt slide and crack like vinyl. Plus it lets the most light output through because the coats are so thin. Have it done by someone who knows what they are doing though.
only really cheap vinyl tint will crack. and if it slides, thats all install error. ive had the vinyl on my headlights for a few years. not a single issue. never moved, no cracks. no discoloring. but its also not ebay junk. use Lamin-X if your gonna do it. there is no better headlight/taillight vinyl.
if ur gonna paint them use nightshades. i used it on my last car and it was great. it goes on evenly and you can smoke it as light as you want or go pitch black. personally i like the blacked out look but in nj theyre very strict bout the laws on that stuff so id go with the film because it can be taken off if the cops harass you too much or if you decide you dont really like it
Im with Ashley on this one. Maryland is very strict about the tint laws and I have had the tint stripped from my Mustang. I had to remove the tails cause I had them completely blacked out. I would try the tint and see it you like it, then consider going permanent with the spray if you do. Good luck and Mazdaspeed!