2003 SUBARU WRX Tires Problems

THERE HAS BEEN NO ACCIDENT OR CRASH. THIS IS AN ONGOING SAFETY PROBLEM WITH A MODEL OF TIRES. THE TIRES ARE KUMHO SPT 225/45R-17. THESE TIRES HAVE SERIOUS DIRECTIONAL STABILITY ISSUES. THEY MAKE THE CAR VERY SCARY TO DRIVE IN CROSS WINDS. IN CORNERS, THE CAR ALWAYS FEELS LIKE IT IS SQUIRMING AROUND AND YOU NEVER REALLY KNOW WHAT DIRECTION IT IS GOING TO GO. I'VE ALIGNED THE CAR TWICE, BOTH TIMES ADDING MORE REAR TOE IN TO INCREASE STABILITY. THIS HAS HAD ALMOST NO EFFECT. I'VE TRIED A NUMBER OF DIFFERENT TIRE PRESSURES. HIGHER PRESSURES (ABOVE 40PSI) HELP, BUT DO NOT FIX THE PROBLEM. I'VE USED SEVERAL OTHER TYPE AND BRAND OF TIRES ON THE CAR AND NEVER HAD ANY STABILITY ISSUES WITH ANY OF THEM. THERE IS NO PROBLEM WITH ANY OF THE COMPONENTS IN THE SUSPENSION SYSTEM. I'VE SPENT OVER ONE MONTH WITH KUMHO TRYING TO RESOLVE...