XP Series 409 SS Turbo-Back Diesel Exhaust System (S6104409) by MBRP. Series: XP Series. Exhaust Pipe Material: 409 SS. Exhaust Type: Turbo-Back. Main Piping Diameter: 4in. Muffler Sound: Moderate. Exit Location: Single Side Exit. With Angled Rolled End Tip. Tip Outlet Diameter: 5in. Tip Material: T-5051 Stainless Steel. CARB Compliant: Yes. MBRPs XP Series is the performance exhaust of choice for the enthusiast who needs a system that can take anything that the road throws at it. This systems rugged sixteen gauge T409 construction can be counted on to withstand everything from salt to rocks, tar to grime.