I’m considering buying a Garmin c340 navigation system, as I will be spending a lot of time tooling around the Austin area, which I am not terribly familiar with. How well does this unit work? Is there a better unit for a comperable price? And as far a GPS technology is concerned, do the roadways stay updated, as far as recognizing newly constructed roads, or roads that are closed? It seems like Austin is constantly undergoing road construction, and I would hate for my purchase to be out-of-date in a matter of months due to a web of new roads being constructed. Any way to keep it updated?