Racing rearsets generally give you a little more ground clearance, grip on the footpegs and feedback about what the rear tire is doing over stock footpegs.
For long distance street riding, they can be a LITTLE buzzy if your stock footpegs have any rubber on them (and the ZZR does, correct?) as there's no damping anymore, but I don't think it would be too noticable.
I'm a huge fan of Woodcraft... Been using their products for 5 years now... Everything from rearsets to tire warmers and they're great people to deal with. Top knotch quality at a very reasonable price.
Check em out at
www.woodcraft-cfm.com