I like tint on certain cars and if your RL is green I am sure you have the tan interior. Since you have a light interior you should want people to see the contrast between the body color and interior of your car. My suggestion is stick with the original color tint. I would get the lightest choice they make, 35%. 28% is the darkest I would go. If you get it done professionally, you do not need to worry about the tint turning purple - they don't use the cheap Pep-Boys stuff.