The brand of tint I used on my car works very well with navigation systems with no problems at all. It's made by Film Technologies International (FTI) who also makes Sun-Gard films. The particular line of film I choose was their Diamond Radiant which is made with a metal polymer. This gives the tint a zero fade factor and a nice "metal" appearance from the outside. http://www.filmtechnologies.com/index.asp for more information. 20% front, 5% in the back (legal).
