Has anyone looked into installing a secondary (redundant) GPS system on your car? I don't want some rinky-dink battery powered thing for 99 bucks on Amazon. I'm talking about professionally installed/hardwired. I understand there is already a GPS installed via your phone but it's pretty easy to disable and I'd love to have a backup. If you know of any shops that offer installation in the SF Bay Area please let me know. thanks, Bill