Not to sound like a weight weenie but how many grams less does a new set have to be to be a noticeable difference for the average rider? This would be for my wife and she's fairly sensitive to her equipment and can tell me when things feel different either bad or good (ex. she can tell when I've tuned her bike and in skiing when I added beveled edges to her skis--they tipped and turned easier).

Any recos? I'm after the best bang for the buck--she doesn't need Dura Ace C24s. The current wheels are Maddux R-3.0s at about 2000 g for the pair. The new wheelset would have to accept Shimano 9 speed. Thanks.