If you’re looking at upgrading your vehicle’s muffler, and want to get the best one for the sake of its longetivity, then you should go for a muffler that is made of 304 grade stainless steel. 304 grade stainless steel has strong anti-rust properties, thanks to its high amounts of chromium and nickel contents, that make 304 grade stainless steel the perfect choice of material for vehicle’s muffler than other grades.