Hello this thread is already available in similar form – but: Someone knows a really good FM transmitter. Such a cheap part for 10 Euro does not work !! Has distortions and a bad frequency response. I need the part for an Astra H with CD30/MP3 radio . The CD part is good again and again – this is known at Opel. A USB adapter for looping costs almost 200 Euro. Alternating the radio is not possible , since the onboard computer is integrated with . So easiest solution – d his transmitter !!