2002 LEXUS SC430 Engine And Engine Coolingexhaust Systememission Controlcatalytic Convertor Problems

MY SC430 HAS HAD A STRONG SULFUR SMELL FROM THE EXHAUST SYSTEM (AFTER MEDIUM TO HEAVY ACCELERATION) SINCE IT WAS NEW. WHEN I FIRST MENTIONED IT TO THE SERVICE DEPARTMENT THEY TOLD ME I NEEDED TO PUT A FEW THOUSAND MILES ON IT AND IT SHOULD GO AWAY. I GAVE IT SEVERAL THOUSAND MILES AND IT DIDN'T HELP. THEY THEN CHECKED IT OUT AND TOLD ME THEY COULDN'T FIND A PROBLEM AND REFERRED ME TO A SERVICE BULLETIN THAT SAID I SHOULD TRY A DIFFERENT BRAND OF FUEL. I TRIED EVERY BRAND OF FUEL SOLD IN MY AREA (CHEVRON, UNION 76, SHELL, MOBILE, TEXACO, ARCO, ASTRO, ETC.) AND NONE OF THEM MADE ANY DIFFERENCE. MY DEALERSHIP THEN RAN EXTENSIVE TESTS ON MY VEHICLE AND SAID IT WAS PERFORMING NORMALLY. I'M EMBARRASSED TO HAVE ANYONE RIDE IN MY CAR. I REQUESTED LEXUS BUY IT BACK AT KELLY BLUE BOOK PRICE AND...