The turbo manifold supports the turbocharger and withstands temperatures of up to 900 °C: it is the most highly stressed part of a turbocharged engine. A free-flowing design builds boost sooner; a suitable flange allows you to install a larger turbocharger than the original and therefore target a different power level.

Material choice matters just as much as the design. Cast iron withstands heat cycles without cracking and dampens vibrations. Stainless steel is lighter and allows better designs, but requires well-designed supports: a cantilevered turbocharger will eventually tear open a weld.