MBRP Exhaust Aluminized Steel, Cat-Back System. Heavy-gauge Aluminized Steel tubing helps to resist dings and dents caused by debris under your vehicle. This material can be a great choice for you if you live in a dry climate that doesn’t see much precipitation, or if you’re looking for great sound on a budget. All of the tubing is mandrel bent for maximum exhaust flow. Mandrel bending ensures no rippling in the bends. The end result is that it gives you more fresh air inside your engine’s cylinders, allowing it to produce more power and improve vehicle performance and longevity.