From what I've seen, those are already pretty good wheels. I upgraded from Shimano RS10's that came stock on my Cannondale, and threw on the Vuelta Corsa Lite wheels and there is a huge difference not only in terms of durability (I've had to true my RS10's every 400-500 miles, whereas my Vuelta's only needed a very small lateral adjustment after 850), as well as weight and feel. It's pretty easy to get better wheels than RS10, though. If anything, you might be saving weight as I have not been able to find specs regarding your current wheelset. Ultegra wheels are a very good competitor to the Vuelta's being in the same price range.