Downpipes are a very important upgrade on turbocharged vehicles. Downpipes connect from the turbo to the midpipe or catback of the exhaust system. A factory downpipe can be restrictive by design where an aftermarket downpipe can greatly improve exhaust flow. Downpipe designs can gain improvement from the collector or flange at the turbo connection or even just the overall diameter of the piping. Turbocharged vehicles really do not need any backpressure or restriction. So the more you can allow the exhaust to flow, the greater performance you will achieve. With less restriction comes a much more audible tone. Some downpipes feature high flow catalytic converters where others are designed for competition race use only.
Agency Power High Flow 200 Cell Catted Two Piece Downpipe Mercedes Benz A45 AMG | CLA45 AMG | GLA45 AMG