2001 BMW M5 Tires Problems

HI, I PURCHASED A PAIR OF MICHELIN PS2 HIGH PERFORMANCE TIRES FOR $600 FROM TIRERACK.COM AND NOTICED THAT THE LATERAL TREAD / GROVES ARE BLOCKED WITH EXCESS RUBBER THROUGHOUT BOTH TIRES. THEY WERE INSTALLED ON 12/06/2008. I RECEIVED DOCUMENTATION FROM ANOTHER TIRE MANUFACTURER THAT STATES THE LATERAL GROVES PLAY AN IMPORTANT FUNCTION TO DISPERSE WATER TO MINIMIZE HYDROPLANING. CURRENTLY, TIRERACK DENIES MY CLAIM FOR AN EXCHANGE. I CONTACTED MICHELIN AND THEY REFERRED ME BACK TO TIRERACK. HTTP://WWW.YOKOHAMATIRE.COM/CUSTOMER_SERVICE/CONSTRUCTION_TREAD.ASPX THE BLOCKAGE IS DIFFICULT TO REMOVE AND WOULD REQUIRE ME TO USE A SHARP UTILITY KNIFE TO MY TIRES. I AM NOT SURE WHAT MICHELIN WOULD SAY IF THEY KNEW I TOOK A KNIFE TO MY TIRES. TIRERACK SO FAR HAS DENIED MY REQUEST FOR AN EXCHANGE CLAIMING THE PROBLEM IS COSMETIC AND WOULD GO AWAY. I DIFFER BECAUSE THE PROBLEM BLOCKS A FUNCTIONAL SAFETY AND PERFORMANCE AREA OF THE TIRE AND PREVENTS...