One thing that's changed is that people are keeping their vehicles
longer and are willing to spend a little extra up front for something
they are going to live with for ten years, and those with older vehicles
that still have a DIN or double DIN opening for a head unit are willing
to replace it with something with more capability, not just digital
radio, but Bluetooth, iPod control, AUX-In, etc..


A fairly recent issue I stumbled across on aftermarket upgrading auto
radios is the CAN_BUS linkage of just about anything, including the
radio, to the rest of the the electronics in the car.
It creates a whole new headache above and beyond getting the replacement
radio to fit in the opening and matching the wiring harness.

Steve
N2uBP