Hey everyone I have a 2006 z4 3.0 si and I’m trying to get a GROM usb3 unit to play through it, I have gone through all the fault finding options with GROM in the states and returned the unit which checks out fine, Grom were adamant that the radio needs coding so I have sent it to a bmw specialist and they have told me that the radio will not accept a cd changer upgrade at all and everything they have tried has been rejected, so I’m not sure where to go from he, does anyone know how I can get around this problem of how I can get hold of a head unit that will Work with my Grom box. Many thanks Steve