Practical? My Navigon has worked flawlessly without the need of an additional GPS chip AFTER I mounted it near the top of my dashboard. It didn't work too well when sitting in a cup holder in the center console though.
Same here. I am using it with the Griffin WindowSeat and it has been absolutely perfect! The built in GPS for the TomTom Kit is in my opinion only useful for the iPhone 2G and the iPod Touch. The 3GS has perfect GPS signal/strength for me