The famous RRC manifold is a genuine Honda part. However straight out of the box it needs modifying and will not fit the K20. Ours are modified here in the UK on our CNC vertical machining centre, and are therefore ready to fit straight onto a Civic Type R EP3 or Integra Type R DC5. This is the best inlet manifold available for the K20A engine and it out performs most other manifolds through the whole rev range. With Hondata K-pro this manifold can give +20BHP. To fit this to your original K20A/K20A2 you will also need an RRC Adaptor Plate (for the throttle body) which is included in this price. The slam panel on both the EP3 and DC5 will need trimming slightly to accommodate this chunky manifold.