Akrapovic Exhaust System for Porsche Cayenne/Cayenne E Hybrid/Coupe (536/9YA) OPF/GPFS PO TI 11H EV Evolution This exhaust is constructed from high grade lightweight titanium and features a central muffler that expands to produce two sets of tailpipes, with a choice of either a titanium or carbon fibre finish designed to complement the lines of the car. Two valves on either side of the muffler control the airflow and are contained in valve housings cast in the Akrapovic in house foundry. Fully ECE type approved, the Evolution Line