I got mine tinted by the the guy who services the biggest Merc dealer in the city. He put on what or local laws permit;
35% front
65% rear
80% back window
My car color is black with black trim. Have to admit, when she is all cleaned & polished and with the GoodYear F1 tires, it gets alot of looks.
From a practical standpoint, it's cooler in the car in summer as well.
Rgds.