Could not find any posts on this subject. Does the addition of an aftermarket NAV/DVD player void the warranty?

I would add it in the compartment where the factory nav would have been. I was thinking of doing something similar to the following mod done on a skyline.

 

A dealer can only void your warranty if they can prove something you added caused the problem. They may try to tell you that it will void your warranty and may use it as an excuse to get out of fixing your car, but legally they must fix it or prove you caused the problem.

They also can't void your whole warranty either, just the part that they can prove you caused damage to.