Akrapovic Exhaust System for Audi RS6 Avant (C8) OPF/GPFDP L AU SS 1 Downpipe Link pipe set (SS) was tested and developed together with Evolution Line (Titanium) system. If the Evolution Line exhaust system is combined with the Downpipe Link pipe set (SS), the link pipe sets L AU SS 6 or L AU SS 8 are not needed When combined with the Evolution Line (Titanium) exhaust system the addition of the optional stainless steel Downpipe Link pipe set (SS) will deliver a unique sound experience: from a low down