To put things in perspective.
D Jetro is worth say $1000? What's it gonna cost to pull the intake off, drill cylinder 3 and 4 runners for the MAP sensors positions and put it all back together. Let's call it $3-400.
L Jetro. Cost of ecu itself is $700 second hand. IF you need Nismo AFM's, let's call that $500 second hand or $700 new.
That's $1,400 either way
A Link G4 would be something around the $1,800 zone. No drilling, far more advanced ecu, can support things like ethanol sensors if you need it later on. (Never say never)
All of a sudden the old dinosaur FC isn't such "value for money" anymore.