well if u can splice a ce1 dash harness to a ce2 harness why cant u make the 7-8 splice to the engine harness? its a very simple wiring job u can tackle in a few hours.
ecu gets 12v. constant
wire 23 from ecu get rlayed 12v
fuel pump ground to wire 6 at ecu
switched power to coilpack
vvs from ecu wire 65 to cluster if it has the vss from cruise control
any a few other small splices a confident person can do.
u use ur factory headlite harness and everything else. even getting the tack to work on the older cluster is pretty simple.
i think theres more to go wrong splicing the ce1 stuff onto a ce2 harness than anything else, beside if u make an error u may have ruined 2 harnesses instead of just one engine harness.
just my opinion, u should worry about mounting first.