The majority of the Nuvi series permits changing the "pointer" vehicle into a custom one. If you're not sure, look up the applicable model number and feature compatibility on their website. https://buy.garmin.com/shop/shop.do?cID=134
If you are not sure how to change the pointer here are the instructions
How to Install:
1. Connect your Garmin GPS device to your computer.
2. Click Download.
3. Click Open, if necessary.
4. Click Extract.
5. Browse to find the “Garmin/vehicle” folder on the Garmin drive, and click Extract.You may need to create the vehicle folder.
6. Double-click the Unplug or Eject icon in your system tray. Click Stop, and then click OK.
7. Unplug the USB cable from your Garmin GPS device.
How to change your ride:
1. On your GPS device, touch Settings.
2. Select Map.
3. Select Vehicle.
4. Choose your favorite vehicle.
http://upload2.net/page/download/JNseClLyXXLSk4t/z4_gray.srf.html
If you are not sure how to change the pointer here are the instructions
How to Install:
1. Connect your Garmin GPS device to your computer.
2. Click Download.
3. Click Open, if necessary.
4. Click Extract.
5. Browse to find the “Garmin/vehicle” folder on the Garmin drive, and click Extract.You may need to create the vehicle folder.
6. Double-click the Unplug or Eject icon in your system tray. Click Stop, and then click OK.
7. Unplug the USB cable from your Garmin GPS device.
How to change your ride:
1. On your GPS device, touch Settings.
2. Select Map.
3. Select Vehicle.
4. Choose your favorite vehicle.

http://upload2.net/page/download/JNseClLyXXLSk4t/z4_gray.srf.html