This is a old thread, all done at chipped uk.
You want to look at lists from the courtenay sport RR national meets you wil get a better picture.
TBH Most cars that have \ pre-cat \ 4-1 mani \ ported TB \ Exhaust \ Filter \ Map \ 200 cat may see 160bhp With cams you may get high 160 to low 170's. it costs £££ to tune NA's with not that much gain.
Dont forget most of these z22se's are now getting on a bit now as well.