2008 Volkswagen Passat Tires Problems

I PURCHASED TIRES FOR MY 2008 VW PASSAT TURBO 4 DOOR SEDAN. I SELECTED FOUR COOPER CS4 TOURING TIRES. I BOUGHT THEM ABOUT A MONTH AGO, SEPTEMBER 17, 2012. ALMOST IMMEDIATELY AFTER THE INSTALLATION OF THE COOPER TIRES, I NOTICED A PULSATING NOISE WHEN THE STEERING WHEEL IS TURNED EITHER LEFT OR RIGHT; THE NOISE FREQUENCY IS A FUNCTION OF SPEED. SO, TWO DAYS LATER, I BROUGHT THE CAR BACK TO THE DEALER. A MECHANIC CHECKED THE TIRES, WHEELS, AND MOUNTING; HE COULD FIND NOTHING OBVIOUSLY WRONG. SO, I TOOK THE MECHANIC FOR A RIDE. HE HEARD THE NOISE, AND TOLD ME THAT IT WOULD DISAPPEAR AFTER THE TIRES WERE BROKEN IN OR WORN IN. THE NOISE HAS SEEMED TO INCREASE OF LATE. I AM CONCERNED THAT THE TIRES MAY BE DEFECTIVE. WHAT DO YOU THINK? *TR