Temp gauges are basic instrumentation and needed.
Personally I say every ECU should have a cell blocker that xmitts within the car when moving, and as for GPS, they are more than worthless for me, so many times the damn thing has ya turning onto non existant roads, and is forever saying recalculating, tossed it out of the truck long ago, I know every paved road, logging road, fire road and deer trail in my area, dont need the thing, LOL
And yes I have a cell phone, a prepaid trac-phone that spends it's life in the glovebox. I put the battery in when I need to make an emergency or long distance call, that is if you are in a area that has any reception, for safety ya have a CB for quicker response.