The BEST sounding exhaust on the market for your BMW 335I or 435I F Series is from Agency Power! Have heard many other systems, we wanted to create a unique sound with our intricate piping design. The Agency Power 335i, 435i exhaust gives the N55 turbocharged engine a very clean, non-burbly, race sound. This exhaust sounds like nothing else ever created. We guarantee you will be blown away! The full catback system is 3-inch made from 304 stainless steel. It has been polished to a perfect show finish and designed to be used with the stock or aftermarket downpipes. The exhaust features an anti drone tube to help cut down on low rpm cabin resonance from the 8-speed transmission. It also features a flex joint to move with the high horsepower and torque your engine will output. The exhaust includes a resonator on the mid-pipe which helps creates this thoroughbred sound. Finally, the muffler features a beautiful Y design that crosses to each exit pipe through additional resonators which output to the rear bumper featuring a 3.5-inch titanium tip with our signature AP logo.