Cobra Unequal Length Exhaust Manifold - No Cat - GT86 & BRZGT86 & BRZ Exhaust manifold Header Cobra 4 1 Unequal Length De Cat Manufactured from T304 grade stainless steel, using mandrel bends for improved flow and maximum gains. 42mm to 57mm Bore Tig welded Includes fitting kit and gaskets The de cat manifold has been designed with unequal length sections with lightweight pipe lengths and angles. This precision engineering improves gas flow efficiency by removing the catalyst at the most important part of the