AndyM wrote a review of Continental Grand Prix 4000s Tire on June 17, 2008
I've ridden about 350 miles since purchasing these tires about 3 weeks ago. So far, they've been great. I've been using the GP4000 (non-S) for several years and have had good experiences with those as well. I'm not sure if the GP4000s tires are actually faster, but they FEEL a bit faster. It might be psychological, but I'll take the speed wherever I can get it.