The CTS B5 A4 1.8T High Flow Cat Pipe Designed to seamlessly fit in place of your restrictive stock catalytic converter, which is situated immediately after the turbocharger. Our test pipe features 3″ stainless steel piping, smooth mandrel bends, two 02 sensor bungs with an option for a third. Substantial power gains, improved exhaust flow and a more throaty sound are the main benefits from installing our test pipe. Upon inspection you will notice a flare which is nearly 4″, this flare then tapers to 3″ and is designed to allow for optimal flow as the exhaust gas transitions from the turbocharger to the test pipe. In addition to being one of the best bang for the buck performance upgrades for A4 owners our cat pipe is also a very attractive piece. Each 3″ test pipe is mandrel bent, hand tig welded. Do you need an additional 02 bung for data logging? Well that’s no problem! Tig welding additional 02 bungs can be done for an additional charge. Product Details: T304 stainless steel construction Mandrel bent stainless steel Fully tig welded design Install hardware included Great power upgrade To remove the CEL that will occur, proper tuning software must be used. Use of stage 2 software upgrade is strongly recommended. DISCLAIMER: This product is sold for competition use and is not recommended for highway or street use. WARRANTY: All CTS Turbo products are warrantied against manufacturing defects for a period of 12 months from the date of invoice. Warranty does not cover abuse, misuse, consequential damages, normal wear and tear, improper installation, or damages resulting from racing. Warranties only apply to the original owner. If a product is found defective the customer will receive, at the discretion of CTS Turbo, free repair or replacement. Warranty on other manufacturers will be processed under their terms.