Your interior is Swing, the only grey available at the time that car was ordered. It was discontinued in the next model year when Soul (black) and Platinum (pale grey) came out. Swing trim parts are neither particularly sought after nor offered for sale very often.
@A2Steve or one of our other breakers would be your best bet if an early car comes in at end of life. Failing that, since the black dashboard and pale grey roof and A+D pillar linings in your car were common to all interiors except Twist beige, you have plenty of opportunity to mix and match from the Soul and Platinum colour schemes as you replace worn trim items, to create a unique interior of your own.
The headunit will be more difficult to do anything about. Non-OEM headunits don't play well with BOSE, if at all. In terms of OEM possibilities, the Chorus II headunit that the car has now is not the one that would have come with it originally. That was probably a Concert I which was also a radio/cassette. Assuming that a CANBUS modification was done to the to support the second-generation headunit it has now, the only other single-DIN choice is the Concert II radio/CD. But the sound-processing internals of the two units are probably much the same, and with a 6CD changer in the boot, would you need to do this? The only advantage I could see would be that you could take the CD changer offline, fit a Bluetooth adapter into its input socket in the headunit for music streaming and hands-free, but still be able to play CD's one at a time.
The only real OEM ICE upgrade you could do would be convert the dash to double-DIN with the appropriate cage, and fit an Audi RNS-E. As well as providing navigation on-screen and with directions in your DIS display, it plays music from SD (Mk1) or SDHC (Mk2) cards, works with the CD changer and can be coded for BOSE. It has its own internal pre-amplifier so it is a step up in sound quality, even before you put that output through BOSE. It has a separate AUX-in to which you can attach a bluetooth adapter for streaming at least, but I'm not sure where hands-free comes into that picture - I don't do phones in cars so I don't have one on mine. The man to talk to about a dash and RNS-E retrofit and all aspects of trim, electrical or ICE is Tom
@timmus, legend of this club. Lucky you, he's in Lancaster so not a huge distance away