from the Continental website:
The all black Grand Prix 4000 S catches the eye with its big silver labels. Aggressive and posh alike it matches every high-end racebike perfectly. With the reduction to black and silver the Grand Prix 4000S does not clash with the frames` colour or rim stickers. S stands for sport, special and “schwarz“ – the german term for black.
But the Grand Prix 4000 S can do more than just look good. With the new Black Chili Compound rolling resistance is reduced by 26%, grip is increased by 30% and mileage is increased by 5%.