Ok. I have gotten all the parts for my OBDI conversion:

VEH: 91Si
ENG: B16A3
ECU: Pr3

new parts that I have;

ECU: reprogrammed P28 setup for Hondata s200 (from Hand Command)
DIZZY: www.rpmpartz.com / B16 OBD1 Dizzy w/ OBD0 plugs - no hassle
HONDATA: OBD0 - OBD1 conversion harness - no hassle

Now here is my question. I can get wideband 02 sensors for $75 shipped. Will I need to replace both of my 02 sensors w/ wideband, or just the 1 @ the cat? I have looked into www.plxdevices.com but I will have enough boxes in the car when I get the laptop end and I am trying to save space.