Most of the GPS units garmin offers in stores (200, 205, 265, etc) come in either the 3.5 or the 4.3" screen. There are no nuvi units with a smaller screensize; least that I am aware of.

most (if not all) of Garmins GPS units for the car are voice prompt. This unit has a voice prompt but it will not voice the names of streets; only estimated feet/meters before turning. For example, the unit will say "Turn left in 300 feet." If you want a unit that will speak the names of the streets, upgrade to a 265T or better.
The store warranty is only 15 days; the unit is treated as a computer in wal-mart return policy terms. You get a 1 year manufacturers warrant good for any manufacturer defects in workmanship and operations however you can purchase a 2 year extended warranty via wal-marts Product Care Plan for about 20 bucks extra, which covers much more than.

The unit should be usable during the "charging" in the car; that is why the unit comes with the car adaptor as opposed to a in home charging kit. Methinks the unit you have may be defective. contact Garmin or you can bring the unit with you receipt to the wal-mart store and exchange it for another.

2007

Yes, it have tested by going the wrong direction. Works very well.

The screen tells you not to,but you can. I set it high on windshield that I can still view road in peripheral vision and do all sorts of things on it all the time.it will allow you to do it , yes.Sounds as if you were talking about the qualcomm on trucks when you said wont allow you to use while moving :-)

yes its like taking your phone charger from one vehicle to another very simple.

yes, garmins webpage will have all the info you need.

no it doesnt have text to speech. but it is voice guided.

yes.