Basic mods people do:
Turbo back exhaust- better flowing especially in top end.
FMIC- depending on plans for car.
Boost controller- increase boost, standard turbo 10psi, 12 Max.
Air filter- panel better in standard box as said above.
Sway bars- front and rear if possible for best handling.
Strut braces- ordered through importer from Japan.
Coolers- oil, trans, depending on Wat car will be used for.
Turbos- high flow of standard, high flow + 3076 internal conversion an frot housing changed, 3076r. All with braided lines.
Brakes- better pads, and new rotors, or upgrade to r33 or r34 brakes with slotted rotors and good pads, or brembo with more modifications.
Head work- cams, cam gears, oil restrictors (I believe are needed in the neo's.
Suspension-full adjustable arms
Coilovers/lowered springs- depends on wat the owner prefers interms of stiffness and adjustability and use of car as too Wat is best for the car.
This is basic list. Depending on price and how far u want to go. And Wat the car is used for. On phone so can't put wat is best when. But as most people would hopefully think he same, always try to upgrade ur handling and brakes (ie safety stuff) before starting in power. I find ways the point in the power if the car can't stop or handle a corner.