AWE Tuning Audi B7 A4 3.2L Touring Edition Dual Tip Exhaust - Diamond Black TipsSophisticated, refined, and powerful, all at once. Each cat back system features an H pipe crossover tube at the front to maximize exhaust scavenging for maximum power, as well as to take a harsh edge off the exhaust sounds. Tubing diameter for the entire system is 2. 25". The more civilized of the family is the A4 3. 2L Touring Exhaust. This system features front, central and rear resonators to keep overall volume to an acceptable level. AWE