stock ecu swap from obd0 to obd1

OK I’m gonna start with this as a base the gen 3 teg had about 10ish more horse power now as far as I know there ain’t much difference in a a1 and b1 head so is most of this power in the ecu? So with that established I’m proposing a obd0 to 1 swap with (future swap) but I’m gonna run a stock ecu for now what kinda power gain should be seen

Mods
Stage 2 clutch
Short throw shifter
2.25 cat back
Test pipe
No name header
Short ram intake
Es trailing arm bushings
Es trans stabilizer kit
Tein lowering springs
No name racing seats
Previous owner said head work was done but not verified by me

Mods to come real soon will be…
Itm
Cams (not sure on which ones yet)
Throttle body
NEW OEM MOUNTS WITH ALL ES INSERTS

No im not going Ls vtec thanks for all the help I can get