I am thinking about tinting my daily driver, 2013 VW GTI, and I went to a shop today and this place uses "Johnson Window Films"? I have never heard of this brand, is it any good? I have been using "Lumar" tint for years with great success but my usual tint shop is "in between" on technicians so I'm thinking about giving this other shop a try. Also, this Johnson film has metal in the film, i've heard that tint film with metal can negatively affect cell phone/GPS/Internet reception? Is this BS? Any feedback is appreciated! Thank you