A d16-GOd on honda-tech told me this

Spade (3:03 PM 5/12/2003): For wiring your going to need a 4 plug o2 sensor, and plug. Because the HX has a wideband O2 sensor. You can sell that thing for about $175. IM RSZero1, he just did a HX to EX swap. Only difference is he swapped the whole engine. Oh, you will need a knock sensor too. Check your engine to make sure you have one now.

I have no idea what any of tat means thougH??