Just get the tint done the entire span of the rear window. In your car the 3rd brake light is probably molded into the rear speaker console and everything, like I said, I've had mine for 3 years now, not a word about it.

 

heeps were exempt till 96? i think. i dont have my book here, but its in there under a bulletin i think

*edit* does the car in question have a spoiler with a 3rd brake light? if so, disable the one in the back glass, and remove it, and its legal.