This Stealth version of the B5 S4 2.7T cat back is the milder of the two systems offered by B&B however don’t let that fool you. With precision hand crafting using 100% T304 stainless steel, CNC mandrel bent tubing and B&B’s proprietary Purge Resonance Technology (PRT) design mufflers this system still offers a nice exhaust note with increases in horsepower and torque. The simple in design yet unique in theory PRT mufflers allows for a deep sporty note on hard acceleration but offer a mild tone while cruising without the unwanted interior resonance. For aesthetics B&B choose their twin 3.5” round double wall tips for a bold yet distinguishing look. Like all B&B exhaust system this cat back is backed with their limited LIFETIME warranty.