The shark fin aerial on my C250 CDI Coupe gives very poor DAB reception on the NTG4.5 Comand head. Even if you tie the station(s) reception is v poor compared with my Fiesta ST and other sets. I gather there are amplifiers in the cabling to enhance signal (is that right?) - if so they're not much use! My MB dealer acknowledges the poor reception but says it's working properly and there isn't an MB upgrade. Can I readily access the fin aerial from inside and replace it with a proprietary amplified FM/DAB/GPS roof mast aerial with (presumably similar fakra) connectors? I've just replaced my wife's W209 faulty Comand 2.0e head with a 7" windows CE-based DVD/Bluetooth/Satnav head and successfully linked it to the Bose speakers so I'm happy to have a go with the C Class coupe aerial to be able to still get "Planet Rock" now it's moved!! Any advice welcomed.