have keven clifford tint them. 2 parts clear 1 part black 2 coats is what i have. 3 coats is a little darker. when the park lights, brake lights or back up lights are on you can't even tell they are tinted. i had all mine done when i worked at a body shop.
trailblazer, they are darker in person but the camara made it look not as dark.
http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs184.ash2/44679_10150233760290277_537465276_14189578_4227617_n.jpg
ctsv
http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs365.snc4/44785_10150233761680277_537465276_14189636_2967306_n.jpg