In a new car radio with GPS, how does the map get into the radio? Does
it receive cellular data, wifi, or come already installed?

What if you want to install the next year's version?

My current 2005 toyota has a map on DVD, and it's not got all the roads,
even the ones that existed then. A repacement DVD is 90+ dollars!
but mine is good. OTOH, one for 2011 is only $20, but I'm guessing it
won't work right??? And I don't know if it has many more roads or not.
Maybe it only has more recent stores.

And I don't see anything newer than 2011, so I figure they don't use
DVDs anymore. ??

I don't need navigation, only occasionally to know where I am.

If the GPS map on new radios isn't a lot better than what I have, I'd
rather save a couple hundred dollars and get a radio withou it.