Well if it was that easy - I would do that. However, a double din cannot fit where the current display / controller screen is (into the upper dashboard) due to a crash bar running a few inches behind the screen - this is in a Legacy. And there is no mounting hardware to accommodate a single din. And the stock deck is built into the facia faceplate down below and connects to the A/C controls via a ribbon cable - so even that will be a challenge to replace as well. But thanks again for your advice though.
Does anyone else have any more specific ideas about the constant rebooting of the Panasonic? Incidentally - it looks as though once the car is parked - it does not reboot - I had it on the other day fiddling with it for at least 15 mins - and it never rebooted. The engine was off as well. I don't know if when the engine is running has something to do with it.....?