The Audi TT 225 comes equipped from the factory with a K04-20 turbocharger and Quattro driveline. While a great combination for making power and keeping it on the ground, the two leave very little room for a large exhaust system. The factory 225 downpipe starts out over 3" in diameter, but quickly reduces and splits into two smaller pipes. These two pipes twist to clear the driveshaft and meet up with two small catalytic converters. 2.55" exhaust piping finishes up the remainder of the downpipe. While larger than a stock GTI downpipe, we certainly wouldn't call the stock 225 downpipe 'performance.' In fact, the stock K04 is simply begging for a 3" upgrade. To date, a 225 3" downpipe has been tackled by few. Tight fitment and custom fabrication costs have kept most from attempting the project. We certainly understand why! Fitment is beyond tight. From the turbo to the stock cat-back exhaust there is barely room to spare. 42's downpipe slides in with precision. Every angle of installation has been addressed making this 3" downpipe upgrade truly worth the effort. Starting at the turbo discharge our downpipe bolts up with a CNC machined turbo flange. A tight radius bend at the turbo quickly sends exhausts gases flowing downward while also steering clear of critical engine bay components. The first bend has been positioned so that normal hand tools can be used on all bolts. Next, a flex pipe joins from the bottom. The top flange of our flex pipe is studded for ease of installation. Both the flex pipe and the downpipe feature adjustable flanges. These custom flanges allow for precision adjustment and ensure perfect fitment on every TT. Our cat section bolts up next, tucking a Magnaflow 3" high flow cat beside the driveshaft and well off the ground. The cat pipe bends towards the center of the car and bolts up our 2.55" adaptor. This adaptor fits stock exhaust and all aftermarket catbacks. 42's 3" downpipe upgrade has been designed to squeeze all available power from a street or track driven TT. Horsepower and torque increases are estimated at 15hp and 15ft/lbs at the wheels. Power increases can be felt instantly after installation. Midrange and top end power increases dramatically while almost no low end power loss is felt. Boost builds steadily without a major spike in pressure. Our 3" downpipe upgrade is available in two configurations - street or race. Street series downpipes include a high-flow cat. Race series downpipes include a test pipe (not yet pictured). Test pipes and cat sections are available separately for those who wish to change at a later date. Thanks to 42's modular flange design the cat can be easily removed on race day and reinstalled for street use. Dyno results are in! Joe Lucchio of Fourtitude/VWVortex put our downpipe to the test. With his current modifications the dyno showed 9.3 hp and 19.3 ft/ lbs peak gains at the wheels. Gains were proven throughout the RPM range and driveability was greatly improved. FREE SHIPPING TO THE 48 STATES. ALL INTERNATIONAL ORDERS WILL PAY ACTUALL FRIEGHT.