Looking to have windows tinted with a metallic or ceramic film. The metallic tint keeps out the heat 98% and the ceramic 80%. Living in Phoenix, AZ window tint is a must. Have read some other forums and Metallic tint can affect GPS and mobile phone connectivity. Will probably go with ceramic since have not read no ill effects but would like to know if anyone has any personal experience with metallic tint and if it has affect their GPS or cellphone connectivity.