Well, went to see my friends son today, he’s a technician at a large VAG chain, had the unit out of the boot in under 2 minutes!. 6″ (15cm) driver in a plastic box in a polystyrene enclosure!, he reckons they are cheap Chinese rubbish, nowhere near as good as the older systems they used to fit..
I don’t doubt him but, did he get his multimeter out and do any testing or voltage measurements, as Chinese stuff still packs a punch?