It's not just the ECU and Tuning differs the K20A VS. K20A3.

If that is the JDM civic engine (non type r) then it is a K20Z2 it's the same as the K20A3 where the ivtec system is "only" on the "intake" cam and functions as a 12 valve engine when on low rpm mode and opening only one intake valve so that the air swirls for better combustion. The ivtec system on this engine is dedicated to fuel economy in mind. Unlike the K20A/A2/Z1/Z3/ the ivtec system allows the motor to run in 16 valve mode all the time and when it engages, its on both the intake and exhaust rockers, and opens all 4 valves even more at high RPM.