There are a MYRIAD of aftermarket options. Of course for your country Im really not sure, but hands down the best aftermarket GPS unit Ive ever used has been the Hertz Neverlost system. This same award winning technology is part of the Magellan RoadMate 500 and 700 of which the 700 is the best because there is an integrated hard drive with all the map data rather than needing to upload info from the computer each time. Garmins Streetpilot is another popular choice.
<img src='http://members.cox.net/inelson5/330i.jpg' border='0' alt='user posted image' />
<img src='http://members.cox.net/inelson5/wooani.gif' border='0' alt='user posted image' /> The whistles go WOOOO!!! *BUBB RUBB FAN CLUB*