I have a 99.5 and is it me or are the factory windows slightly tinted already? If they are slightly tinted, does anybody know what % tint they are?

Mine is a 99 and it came with a greenish tint.
I'm not sure about the % though. I went to a shop and got my windows tinted, so most of the time it looks black, but on bright days, I can still see that slight shade of green. Also, if you are planning to tint your windows, you have to take into account the % that the car originally has. If your state limit is 35% and the car is built with 3%, you can only get up to 32% film..in my state, they get real picky with that during inspections..

Your statement about factoring in the factory tint percentage is correct, but the percentage number refers to how much light is allowed in. A number like 35% means 65% of the light is blocked. Therefore, the factory tint would be around 90% or so.

.