Be sure to look at real samples of the tint shades you're choosing between, preferable on an actual car. A 20% tint can look different from brand to brand, some have a purple hue, some greenish, some smoky brown. And give some consideration to the level of tint. 20% is pretty dark and what you'd typically see on new cars, 5-10% is limo black. My personal preference is 35% as it is dark enough to give the tinted look without being so dark that you can't see out of it at night time. 50% don't even bother, you can barely tell it's there. Key thing is to look at samples and be aware that tint will appear darker on the car because the other tinted windows will be blocking light coming into the cabin and give the appearance that the tint is darker than it would look if that was the only window that was tinted.