I'm currently riding on Weinmann RM19s I purchased just last season for my Raleigh GP. They're fine, nothing wrong with them, but I was wondering how much difference a stiffer, lighter, better wheelset might make. Would these from Harris be a worthwhile upgrade?

http://harriscyclery.net/product/sun...wheel-3135.htm

Otherwise, it seems I'll be hunting for used wheels since I don't want to respace my frame for 700c wheels and a 130 mm rear hub (right?). Are there any particular kinds I should be seeking? I'd be willing to spend up to, say, $300 if they were really worth it since I could always transfer/sell them whenever I move to a different bike.