How to replace VW Golf radio without losing more warranty on car systems??

Service mgr w/out integrity will not replace 2004 Golf radio under warranty. I want to replace radio/CD/cassette system without ruining warranty on car's other systems. Mgr. is likely to claim something else was harmed when radio was removed. Says only VW tech can install new one and do it properly -- for $600+. It is totally unplugged, so I cannot even insert cassette connector. Car still under warranty with only 30,000 miles. Should I just continue to drive without radio? Only one VW dealer in town, so I suffer even for oil changes (which take 3-4 hours with appointment). Any suggestions?