Vibrant Performance stainless steel race mufflers are densely packed with our premium multi - layered sound absorption materials, TIG welded for optimum durability, and manufactured from 304 stainless steel for optimum durability and corrosion resistance. Vibrant Performance race mufflers are very lightweight, compact, and are designed to comply with muffler requirement rules at race tracks throughout North America. They are available in 5 9 overall lengths and inlet I.D. diameters ranging from 3 to 5.