you don't "need" to replace your current wheel QR - the one already on your road wheel will fit fine unless it's special design of some sort like those with flat or carbon levers. The one supplied is a little more robust and fits the clamp well so if you are in the habit of overtightening the clamp (which is difficult to do anyway) or have a special QR then it may stop your standard wheel one bending or getting damaged. they're easy enough to swap over if needed - a 20 sec job.
Edited: 15/11/2010 at 18:28