Not sure if your tint ratings are the same as we have in the UK, but I originally went for a 35% tint (as shown in my avatar picture) on my first 4.8is, but my second one I chose less tint and went for a 50% on the front (which matches the OEM sun protection glass on the rear windows). The 35% made it difficult to see properly at night, particularly if looking through the door mirrors, also it depends on the colour of your leather. My current car has black seats whereas my first 4.8is had the cream beige leather.

A few pics..

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