A portable GPS navigation device displays map information and navigation instructions; the device includes a two-way wireless transceiver operable to connect to a mobile telephone; is operable to enable a user to control one or more functions of the mobile telephone and includes an audio output and a microphone to enable a voice call to be made using the mobile telephone. The sickle-shaped spoiler is configured to direct airflow generated by a rotating disk and includes a tapered first end portion configured to direct the airflow toward the inner diameter of the disk and to reduce the airflow on the side of the disk opposing the spoiler. A preheat data delivering circuit is adapted to provide the preheat temperature data to at least one preheating element. The surface model represents reflective characteristics of a simulated surface on which display of the input image is simulated.