My 1990 Nissan 300ZX Twin Turbo was estimated at 500hp.

What I did to acomplish this goal was to do the following:

STAGE 1: 320hp @ 10.0 psi GTZ Single Tip, Exhaust System
STAGE 2: 380hp @ 13.5 psi Computer Upgrade
STAGE 3: 389hp @ 13.5 psi Larger Intercoolers
STAGE 4: 402hp @ 14.5 psi EVC (Electronic Boost Control)
STAGE 5: 480hp @ 16.5 psi Super 500 Turbo Upgrade 
Upgraded Injectors 485cc
STAGE 6: 500hp @ 16.5 psi Stillen Twin Hi-Flow System
Also added to   my Z:

DIN Electronics Panel
DIN Boost Gauge, 46mm
Dual Friction Clutch
HKS EGT Peak Meter
HKS M35i Spark Plugs
HKS Peak Boost Gauge
PIAA Crystal Fog lights
Rear Lens & 3rd Brake Light
Short Throw Shifter
Stainless Steel Brake Lines
Stillen High-Metal Pads
Stillen Front Louvered Panel
Stillen Rear Spoiler
Stillen Rear Valance
Turbo Timer & Harness

17 x 9 Adonis Z-5 Ceramic Coated Rims ($595 a piece)


FRONT: Dunlop SP8000 245/40 ZR-17: ($236 for each tire)
REAR : Dunlop SP8000 265/40 ZR-17: ($275 for each tire)