CtRNuT

Probably a noob question but I wanted to know how hard is it to swap a B16b type r into my 99 ek hatch. Right now I am running a Ls/Vtec converted via jumper harness to obd1 running a p30 chipped and fully tuned ecu. I know I would only have to unplug the jumper harness and then what would be easiest to use my stock harness and wire it to the b16b or get an ex, or si? Which would be the easiest way to go? Would it be possible to just use my existing p30 and obd1 set up or no? Sorry I can build motors with my eyes closed but ive always had others do the wiring. Any help would be greatly appreciated.