Just to throw my 2c in... I had (many years ago, in another city...) a fully optioned (moon roof, lsd, analog gauges with 9k rev counter)
1983 ga61 celica supra. Went nutty even after I thrashed it so hard it dropped 2 cyls. Wouldn't die thrashing onward.
Got sick of it not dieing, yammed a 1g-gte from a mk3 ga70 in there (swap sump, oil pickup, engine mounts it will bolt in)
so 1g-gte 7psi model, 600x300 baby-catching fmic, free flowing exhaust, good final drive being in front of a w55 and f283
Went crazy. No engine mods 200something k on it and smoked many tyres and fuckwits on the road, til I had to sell it to move to wgtn
POINT IS - some things are so rare that they are worth more unmodified. If I had unmolested that car, sold it to someone that
thought "omg fully optioned 2000gt celica supra" and spent the extra money on starting with a 1geu auto, it would have
been better for both me and the guy that appreciated it's factory form. Which was pretty a damn sweet form.
End of the day, do what you like, I think it's cool and it'll definitely be more noticeably ballsy with the right piping/exhaust/etc than 1g-ge
But keeping it original or giving it to someone that would never find one otherwise is cool too, and could give you more money for more boost
Good luck with it all sorry bout the long post guys