The Mercedes AMG GT-S 4.0L Bi-Turbo is a monstrous coupe with 503 horsepower to the crank. In addition to the huge horsepower numbers, the cars rear wheel drive puts down 479 ft/lbs of torque making it a real Porsche 911 fighter. Driving the GT-S is already legendary status with the complexity of electronics and control system the vehicle has. Going from Comfort to Race Mode, the car becomes an animal changing exhaust tone and ready to do 0-60mph in just 3.8 seconds. So how do you improve the car further? The M178 engine has proven to see major gains with a few modifications added to the vehicle. Turbocharged engines need a couple of simple things to help them produce more power. More air flow in and more exhaust flow out. If the car did not have all the sensors measuring air flow, having a straight filter to the compressor and a small dump pipe on the exhaust side would make this a wicked machine. But in reality you need to add quality products that help deliver drivable, reliable, and efficient performance.

Upgrading the cars downpipe and midpipe is the biggest change in the performance of the car. Factory downpipes have large catalytic converters that slow down the exhaust flow causing unnecessary back pressure to the turbochargers and robbing the vehicle of plenty of power. Catless down pipes are the ultimate upgrade to the 4.0L Bi-Turbo engine. The straight through down pipes help deliver a serious wheel spinning amount of torque, faster turbo spool, and hard acceleration all the way through redline. With the removal of the catalytic converters, the exhaust is open up and sounds fierce when in race mode, yet still comfortable for daily driving.

The down pipes are made from 304 stainless steel and are TIG welded from a proven JIG for a precise fit. The turbo flanges are CNC machined steel to provide a tight V-Band seal to the exhaust housing of the turbo. To maximize exhaust flow, they start at 3.5 inch at the turbo outlet and then taper to 3 inch for proper fitment and clearance. Designed as a 2 piece pipe including the down pipe and mid pipe to replace the bulky and heavy 1 piece OEM part. The downpipes are designed to work with the stock exhaust system or our full straight through race exhaust. To maximize performance, we recommend doing an ECU flash which will also prevent any check engine lights from coming on due to the catless pipes. The downpipes in combintation with our ECU Flash (seen here) added nearly 100 ft/lbs of torque and 70 all wheel horsepower on a Mustang Dyno with 91 octane! Thats a 14% gain in horsepower and a 19% gain in torque!

The removal of the factory 1 piece down pipes is not as simple. The stock down pipes are bulky and cannot come out as easily as putting the new pipes in. To remove the stock downpipes, you must drop the center driveline tunnel working from both the bottom and top to undo necessary bolts, clamps, and lines. We highly recommend a qualified and experienced shop to perform this service.

Agency Power Catless Downpipes with Midepipe Mercedes-Benz AMG GT-S 15-16 $3,200