Experience with Sony-Ericsson HCB-300 anyone?

Has anyone attempted an installation of the Sony-Ericsson HCB-300 handsfree bluetooth car kit? It seems (from its description on SE's website) that it integrates nicely with the Audio where it can reroute the phone through the speakers and mute whatever else is playing. SE's webiste is pretty poor about explaining what exactly does this thing do and how, I downloaded the manual too but it wasn't particularly helpful. It seems they give you a speaker to listen to the phone through, and if you want to route throught the car stereo you need to get an optional Advanced dMusic Mute gadget called HCE-16 (again, made by Sony-Ericsson).

If anyone has any experience with this, I'd greatly appreciate it. It's similarly priced to the Parrot kit.[/siteimg]