Today I replaced the OEM Business RDS & Harman Kardon setup. Plan was to keep the HK Amp, while updating the car to have Bluetooth phone and music streaming. I chose the Clarion FZ502e head unit for six main reasons: Built in microphone - In a convertible, a mic by the windscreen is not going to work Parrot Bluetooth - I've used these before in dedicated units and work well Streaming Bluetooth for music (A2DP) - Essential today, IMHO USB playback - put anything on a USB stick and play it. I got a SanDisk Skip, mini USB unit, invisible in use. iPod/iPhone direct use via the USB port, if needed Pre-outs for an amp Obviously, some prefer the OEM look, and normally I'm that way too, but the Business RDS unit with a tape deck wasn't cutting it, either with regard to sound quality or features. In place, I actually really like the unit, as the central circular control mimics the other round features of the Z3 interior, and the unit doesn't have myriad coloured buttons or flashing lights, very muted, with a feint blue tint to the text and the blue ring around the control itself. Requirements to install, over and above what shipped with the unit, were: Autoleads PC9-405 harness adapter Aerial adapter, BMW to Fakra/ISO The wiring is a little tighter than before, but luckily there is a fair amount of space back there. Requisite pics attached.