Navigator 5 & Tungsten E2

Anyone using a Palm Tungsten E2 with the bluetooth version of Navigator 5?

I am looking for a GPS system for my tungsten E2 and the Tom Tom Navigator 5 (bluetooth) is looking favourite, however, my concern is the built in speaker of the tungsten E2 which I don't think is particularly loud.

Is the speaker audible above road noise?

Also how long does a fully charged batt last when using the GPS.

Any comments at all on the above combination would be helpful.

Thanks (new user)