lightest wheel that fits a duster ?

Hole shot wheels

That would be a no-no!

Taken from the HoleShot website FAQ
"Can these wheels be used on the street?

No, Holeshot Wheels are designed and built for legal drag racing only and are not D.O.T. approved."

Though I would say they are probably one of the nicest quality and lightest available along with Bogart. Like anything else though, it all depends on what you mean by "street driving" and what risks you want to take.