UHP4 goes on with CD30, CD30 MP3, CDC40 OPERA, CD70 NAVI, DVD90 NAVI, DVD100 NAVI and GID display or CID display with minimum software version 59 on Siemens VDO or with all Delphi-Grundig.
Price: new UHP4, 90 euro, original microphone 20 euro, 32 pin connector and some wiring 10 euro. Plus shipping from Europe.
7 wires to car connections to be done, 2 at the microphone, then programming with tech2 or mdi only. No other tester will work. Car pin code is needed for programming.
I did all above on my Corsa C and sound quality is good!