Downpipes

The downpipe is the first piece of pipe after the turbine, and the one that chokes a standard exhaust hardest. A larger diameter and smoother bends cut back pressure, help the turbo spool earlier and change the sound. Everything here is stainless, made for the engine and for the car.

The versions

There are three kinds: with a sport catalyst (lower cell density than standard, so less restriction), without a catalyst (competition use only), and with a centre silencer section. Where a part has a catalyst, it is stated in the name.

What it asks for after fitting

You will almost certainly need a remap: changing the back pressure moves the thresholds of the oxygen sensors, and without adaptation you get fault codes and limp mode. Check what the regulations you run under ask for as well, especially if the version you picked has no catalyst.

How to choose the diameter

Not everyone should take the biggest pipe. The diameter is chosen for the target power and for the turbo: too big on a standard engine means a lazier response low down. The diameter is written into the name of each part, and some references are complete kits, not just the section after the turbine.