2011 - 14 Mustang GT headers with 1 - 78 primary tubes, 3 X - Pipe and 3 dia catted lead pipes that mate to the factory connection point. Tig welded 304 SS headers with 38 thick flanges and 3 dia slip fit collectors with merge spikes. This system replaces the factory manifolds, catalytic converters and H - Pipe with a superior performing lifetime guaranteed bolt - on system.