Exhaust Systems, Cat-Back Exhaust Systems & Axle-Back Exhaust Systems - Dynomax® Performance Exh, DynoMax® Performance Exhaust is a leading brand of stainless steel exhaust systems, cat-back systems, axle-back systems and stainless steel muffler technology. DynoMax® Performance Exhaust has a complete line of mufflers, including the Ultra Flo X stainless steel muffler, Ultra Flo Welded stainless steel muffler, Ultra Flo SS polished stainless steel muffler, Super Turbo muffler, Race Collector muffler and Race Bullet muffler. Each and every DynoMax® product is built to the brand's theme, 'Pure.