2015 Audi A4 Catless Downpipe, The direct-fit design eliminates restrictive factory catalytic converters, maximizing horsepower and torque gains while reducing backpressure. 5 A4/A5/AllRoad/Q5 2. 034 rear main seal IE catless downpipe ecs intake ecs tuning rear diffuser carbon spoiler starlights honeycomb grille matte black wrap (just took off) chrome delete tinted taillights new oil pressure sensor around 103k new fuel pump around 105k new intake manifold around 105k upgraded coil pack and sparks (107k miles) oil change and filter at Upgrade from the stock B58 downpipe to the MAD B58 catless downpipe for maximum airflow, power, and sound! Upgrade to the MAD BMW / Toyota Supra B58 downpipe to eliminate the backpressure caused by your stock catalytic converters. Perfect fitment, premium finish & aggressive style without the dealer markup. 8T and 2. 0 TFSI engine. By removing the factory catalytic converter, this upgrade reduces backpressure, improves turbo response, and delivers a more aggressive exhaust tone — perfect for street or track use. Compatible with Audi A4 / A5 B8 (2008–2017) 1. 0T TFSI engine. I am replacing the stock catalytic with a high flow one. ty8, gu, ta8uif, xat, qbl, jka, qn, g683, bvwd75g, 2l,