obd 1 or obd 2 ? Si powerplant in EK ('98's)

[pressurecooker]

I dropped my D16y8 98 Si(EX in US) motor & ECU in a 98 hatch that I gutted. It had a B18b & was previously converted to OBD 1. I have no wiring experience & don't know what the previous owner did with all the cabin wiring. Can I plug in my C02s (secondary 02 sensor on CAT) with a sub harness?, or do I have to rip apart the dash & rewire the main harness to accept the 02. I'd like the car as close to stock as possible, it would be nice if I could just plug it in under the dash like the Si. Is the main wiring under both dashes supposed to be the same?, or was the hatch wiring tampered with to accomadate the OBD 1 conversion? PLEASE shine light, what's my best easiest option.

 

[pressurecooker]

moving along

Hatch dash coming out for inspection to route wiring

 

[dtob]

Why don't you just leave it obd1? It would save you LOTS of rewiring.

 

[pressurecooker]

I figure it's cheaper just more time consuming. Everything I put in the hatch is obd2 except 4 the cabin cause the car was obd1, so I pulled my si/ex cabin harness today(basically just dash mounts left) & wiring is out, its pretty cold.
And I also have another swap 2 do in the spring in my Si/Ex(boosted B18b obd1).
So I'm gonna need all my obd1 stuff.

 

[pressurecooker]

I rocked & now I'm rolling. Swap successful yeah baby.