The AWE Tuning S4 exhaust manifolds are tubular in design, utilizing an anti-reversion bulkhead at the collector to maximize exhaust gas velocity.

Though there is ample space for a larger tubing diameter, we use a slight taper at the cylinder head outlets to retain thermal energy and maximize exhaust gas velocity on the way to the turbos. This slight taper requires extensive hand work during manufacturing, but if we can help it, we will never take a performance shortcut just to make it cheaper for us to build a product.

The manifolds are also Swain Tech heat barrier coated with a material used on missile nose cones, in order to keep the heat in the exhaust gasses and out of the engine bay.

Each kit comes complete with studs, nuts, gaskets, and new downpipe heatshields.