Can you please tell us in terms of handling difference once you try this?
I bought a leftover base 2012 early last year. Before I even picked up the bike I sourced some S wheels and rode those for 2,000 miles before putting Bridgestone S20's on the base wheels for a mountain trip for better wet weather performance. The difference was immediately noticeable, although the steering characteristics of the Supercorsa vs. S20 tires also played into the perceived difference.
After putting 1,500 miles on the base wheels with Bridgestones I put the S Wheels with Supercorsas back on for another 1,500 miles. Then, last November I bought the RotoBox Carbon Fiber RBX2 wheels, which are 1.4 pounds lighter than a set of BST CF wheels, 4.25 pounds lighter than the S wheels, and a whopping 9.5 pounds lighter than the base wheels.
I had Supercorsa's mounted on the RBX2 wheels and the difference from the S wheels was ridiculous. When I say ridiculous, I mean I had to learn how to steer the bike again and change some damping because it was so different - steering was so much lighter and direction changes so much quicker it requires a re-calibration of steering inputs. It's not just the absolute weight difference, but also
where the weight is less, which on a CF wheel is significantly less weight around the rim. This equates to lower moment-of-inertia, which in practical terms is the force you have to overcome when steering (changing direction of) the wheel. The difference in going from base to S wheels was not nearly as great as the difference in going from S wheels to Carbon Fiber. However, since S wheels are going for about $1,500, it is an awesome and worthwhile upgrade. IMHO, I would do that before adding an exhaust.
Hope that helps explain the practical benefits of lighter wheels. Here is my thread when I got the RotoBox wheels and tried to relay the experience:
http://ducati1199.com/ducati-1199/16106-my-new-rotobox-rbx2-carbon-fiber-wheels.html