Yes, I was pretty impressed with the stock wheels too. I've also never had rims this nice on a stock car.
As long as you keep them clean regularly, you'll be okay. Don't make the mistake of getting lazy about it b/c you'll want them clean eventually and by then, dirt would've caked on and it might require claying to get the stuff off. Washing once a month in City driving during a drought would be decent. I'd love to do it every 3 weeks or so. Of course that depends on your distance from the ocean, temperatures, parking inside/outside overnight, type of conditions you drive in, etc.