anyone know if this needs a reflash when doing a K20a3 in a 02 ex? I know when swapping the a2 it needs a reflash coming from the RSX, but no one has posted anything about the a3.

 

Nope, it's the correct ECU. If it's modded he might want a reflash though, certainly can't hurt.

 

so the ecu should work without a reflash? I know the K20a2 needs a reflash when swapping it into the 02ex. Do You know if the rsx subframe and cv axles from the Si are still needed for the swap, or will that engine just drop in and the si mounts will work?

 

I have no idea about the swap itself, don't plan on owning either car so never really went in and researched it.

K20A3 IS the engine in the 02 Si, so yes the ECU from the 02 Si will obviously work just fine.