Nismo/Tomei fuel pump
Nismo injectors
Power FC
Z32 AFM
Highflow,GT 2876 or HKS 2835
Upgraded clutch
Upgraded Brakes
Thats the basics, there is a good 6-7k just in parts.Its all a matter of how far you want to go with the car and how much you want to spend.
Once you know what you want from the car and how much you want to spend,the rest is easy.