I tinted my tail lights with VHT Niteshades not long ago. I'm happy with how they came out, but up close they aren't perfect. This could be because it was a little cool when I was spraying them. I kept it all inside except for the spraying, but I can see dots in the spray. Depending on how much work you put into it, you can make them come out perfect. Either way, they look great unless you have your face up to them.
So I took off the tails and wet sanded them with... I think 2000 grit. You don't have to do too much, but it cleans up the surface and roughs it up so your spray will stick. Then I taped everything except for the lenses and sprayed them. You have to be very careful not to over spray. They will get darker after they dry and you don't want runs. Let them dry for a little while. It doesn't need to be long, I think I waited 15 minutes between coats. On your tails, I suggest no more than 3 coats or they are going to get very dark and you'll probably get pulled over. I'm very happy with how mine look with 3 coats, and the red is still there but dark. After you finish with the tint, give them a little longer to dry a little better, then start spraying clear coat. You can really put as many layers of clear on as you want. I was going to do about 5, but it was getting late and I think I fell asleep after 4. Do at least 3 so you get a good even clear though. Let them dry 24 hours, pull off the tape, and start wet sanding again. The clear will have a lot of orange peel until you wet sand again. Wet sand until they are nice and smooth, but be mindful of your clear. Once they are smooth you need to polish them to a high gloss. I'm going to say it would be near impossible to polish them enough without a polisher though. It takes a bit to go from sandpaper to gloss. You'll know when you're done.
That's about it. It's not too bad, but it'll have the lights out of your car for a whole weekend if that's a problem. I just did mine on my pre-winter detailing weekend along with my fogs and added a CDC blackout panel. I think the back looks ten times better now myself and I'd suggest it if you have a little patience and could use an arm workout.
I wouldn't suggest doing your headlights though. I don't know about there in SC, but that's usually illegal, not to mention it'll severely affect your lighting at night. I did 4 coats of niteshades on my fogs because I wanted them to be very dark. They look great when they are off, but if I turn on only my fogs at night, I can't see 5 feet in front of me whereas they used to get me flashed for having them on. 1 coat wouldn't come out even enough, and even 2 coats would be too much I think.
You could easily apply the same way to the side markers and such though. Front markers I'm doing clear and switchbacks, but they could probably use 2 coats.
Here's my final result: