I had 20% on a former red cavalier and I have no pics but damn did it look great. Very dark with the black interior but I did have many problems with cops at all levels...Sheriffs gave me the least amount of trouble but local and State got me anytime they could...Probably had about 10 warnings and 4 tickets in that car in only a few months before I was literally forced to take it off or face having my license revoked in court by the judge.
More recently I had 35% on the front and 30% on the back, which was dark enough and never had a problem with cops..I would get a feel for from others in your area with tint how the police are...My cousin has 20% all around his car where he lives in Vegas and has never had a single problem with cops in 3 years of owning his car....
Upload pics..would like to see how it turns out. Good luck.