GPS info

A friend is interested in installing a third party GPS unit, and is looking for info and recommendations. 
 
Anyone?
 
Thanks.

Alpine / kenwood ..... systems comes with touch screen radio/mp3/cd/dvd and nav system (also rear camera can be integrated).
all available in audio system marker.

Maybe these sites will help:
 
http://www.alibaba.com/catalog/10931050/Touch_Screen_Alpine_Radio_With_Nav_Dvd_TV_Camera_Mp3.html
 
http://www.sonicelectronix.com/cat_i321_in-dash-navigation.html
 
good luck