Prior to purchasing my two pickups I rented a Honda Jazz from Hertz. The Jazz had window tint film, which if I remember correctly was from Lamina. The sides and rear windows had a mirror like reflection to them so I suspect that film had some metal in it. The front windshield did not have a mirror like reflection so I suspect that it did not have metal in that film. I drove quite a bit in the Jazz using my Garmin nüvi 55 and I did not notice any degradation in GPS performance.
When I purchased my 2015 Toyota Hilux Revo Smart Cab 4X2 2.4J, I did not want to spend as much money so I decided to have Toyota Buriram install the 3M Smart Series (FX and FXR) that they normally include as part of a sale. The sales lady asked me what I wanted as far as FX or FXR films and percent tint on the windows. I responded by asking her to make a recommendation. She recommended 60% tint on the sides and 40% on the front. She said that anything darker could be an issue with law enforcement officials. She also recommended FXR (with metal in it) on the sides and rear windows and FX (without metal in it) on the front windshield. She recommended FXR on the sides and rear windows because it is also slightly better with reducing inside temperatures than the FX film. She recommended FX for the windshield because it does not have metal in it and won’t adversely affect the GPS. She was aware that FXR can possibly cause a problem with GPS and mobile phone performance. I was satisfied with her demonstrated knowledge and based on my experience in the rental car I went with her recommendations. To date I have not had any issues with GPS performance in this pickup.
I have been satisfied with the Toyota Buriram service that I have received. I suspect that if Toyota Buriram thinks that they can increase sales or make money by offering Crystalline they will come up with a solution to meet those business goals. That solution may be to get the requisite training for their technicians or locally outsource the installation.