The Zune Car Pack ($79) is Microsoft's in-car FM transmitter made especially for its line of Zune MP3 players (including the first generation Zune). The Car Pack shares the same aesthetic as Microsoft's second-generation Zune players, offering design-conscious Zune users an elegant in-car listening solution.
The Zune Car Pack isn't the most feature-packed FM transmitter we've seen. Unlike other in-car supergadgets, such as the DLO TransDock Deluxe, the Zune Car Pack doesn't come with auxiliary AV inputs and outputs, USB charging ports, or audio adjustment settings. Fortunately, the Zune Car Pack delivers most of the features people want. It looks classy enough to put in your car, works well, and is easy to operate.
The only downside to using the Zune Car Pack as an FM transmitter is the mess of cables involved in the system. With cables running from the Zune to the detachable interface, and then running from the interface to the charging plug, you end up with a manageable (yet unattractive) amount of cable clutter. The good news is all that extra cable acts as an extended FM transmitter antenna, assuring better broadcast quality then we've found with smaller docking transmitters, such as the Griffin iTrip or DLO TuneStik.
During our testing in the radio-clogged San Francisco Bay Area, we were able to find four empty FM frequencies that provided stable reception, two of which offered above-average audio quality. As with any FM transmitter, your results may vary.