I'm not really fluent in these thing's so I have a few ?. I'm looking at a used Garmin GPS Map76-am, I'm assuming that it's a few year's old since I can't find it in my old cabeala's catalog's. Does anyone know anything about these unit's? I know it doesn't have topo, that would have to be downloaded. The guy's asking $125 for it, then I would have to pay extra for the topo stuff, right? Is it complicated to download this stuff from a computer? Thank's.