Heres the flip up display unit only available on ebay:
https://www.ebay.com.au/itm/Volvo-C70-98-04-S70-V70-96-00-Navigation-Pop-Up-Nav-Screen-8633435/263327695924?hash=item3d4f8dc434:g:6-cAAOSwpvZaDZ4Q
Some ppl gut them and hard wire a little navman in there using a $5 gps power supply off the radio feed.
They would be whole lot better than a volvo one. You could hook up a reversing camera too - so cheap now.
The volvo sat nav was pretty crappy to start off with and the maps must be so out of date by now you couldnt use it anyway. There is a guy who sells the updated dvd rom for the P2 cars but getting one for a P80 would be nigh on impossible.
But I prefer the look of the dolby speaker to this horrid plastic thing. The pop up ones in the P80 and later are much nicer