It's a lot of smaller things that add up to the whole.
JDM =
More lock standard
Factory 4age with airbox and other cool things
Better seats
Jdm accel pedal that's even with the brake and clutch
Jdm t50 with the slave cyl on the drivers side
Lip and skirts
Vented front brakes and disk rear
LSD standard
Higher redline on the tacho
Better headlights that shine better and look better
Better looking indicators
Trueno pop up lights for takumi spec!
JDM = non cracked dash
gt-apex had power steering, power windows, power mirrors, climate control
Heaps of small shit that all adds up