Brand new from Treadstone performance is our cast K20 turbo manifold. Will fit 02-05 Honda Civic Si, and 02-up Acura RSX. Those of you looking to make their own turbo kit, this ones for you! Manifold excepts any T3/T4 based hybrid turbo and any 35/38mm externl wastegate. Complete turbo kit will become available within a few months. Treadstone manifolds are cast using a high ductile silicone based iron adhering to a strict ASTM casting standards. 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 a lifetime warranty against cracking. All of our manifolds incorporate external 35 or 38mm wastegate, and either T3 or T4 standard turbine inlet. All internal surfaces are cast smooth for high flow and low surface friction.