I have an 04 Civic SiR with an K20A3 engine for European and North American market. As we all know, the engines for the Japanese Domestic Market (JDM) are way faster and highly tuned. I was considering doing an engine swap for a JDM K20A engine from Japan but I wonder if It makes more sense to rebuild my engine to be similar to the Japanese one. Sine they are the same K series engines with the same base build... I could just buy high performance internals and peripherals to be similar to the Japanese one. What does this include for all the experienced people out there? High compression pistons, new gaskets, piston rings, racing cams, performance cam gear, titanium valve springs and new valves... I have bought an F1 Racing 3 stage clutch and light weight flywheel. I have a T1R full catback exhaust and stainless steel headers. I am planning on getting a new intake manifold and a 74mm Skunk2 Throttle body with cold air intake. I am also going to get the Hondata ECU upgrade. My real question is what all needs to be done to make my engine as good as or better than the JDM K20A? Which do you think is more economical? The new engine is about $5000 plus shipping and duty and install labor. So I'm guessing around $8000 or more. What do you think the parts and labor would cost on rebuilding my engine compared with this? Thanks!!