Its hard to talk anyone out of doing something they really want to do, especially when it looks cool
, but there is a real safety concern with tinted windows beside the driver. If they are too dark, or at night, or in rain/snow conditions, you will lose the ability to have eye contact with other drivers and pedestrians.
Think about it. There are thousands of subtle cues involved in successfully completing a trip by car from point A to point B. Watching what other drivers and pedestrains are doing AND knowing that they have seen you and know what you are doing is absolutely essential on our hectic and congested roadways.
Now take away your ability to see what the other driver is looking at, or denying others the same ability to see what the heck you're looking at. That creates a problem. Insurance companies should, if they don't already, penalize those involved in accidents where lack of eye contact was a factor due to tinted windows (or loud blaring noise from those megawatt stereos :p).
Just my opinion. I know you're gonna do it anyway.