I’m basically in agreement with everyone above, any high quality film between 20-35% will do what you want and look great. Once you get under 20, IMO it becomes a cop magnate and seriously hampers visibility at night. I’ve been in a car with 10% all around, and it’s probably unsafe to be honest. My car has 35% 3M ceramic, and I’m quite happy with it. Down the road I may go a bit darker, but I’m satisfied for the time being.
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Other stuff...652WHP
F30 N55 XDrive EBII