Treadstone manifolds are cast using a high ductile silicone based iron adhering to a strict ASTM casting standards and are coated with a high temperature paint to prevent rusting. These manifolds are very durable and will withstand all the heat and vibration you can throw at them. Our manifolds casting exceeds OEM specifications and now come with lifetime warranty against cracking (view tech page for additional info on warranty). This manifold incorporates a external 35/38mm wastegate port, and a T3 standard turbine inlet. All internal surfaces are cast smooth for high flow and low surface friction.