Realistically Speaking...How much $$$ would I actually need.

2011 Nismo#91

Budget 22-24k for the TT, to do it right and have plenty of room for more power later down the road. Just for you Minsu I'll try and find the build I was looking at doing for a properly done reliable 500 whp.
TT supporting mods and suggestions.
You can cut some costs from there, or add some.

Quafe LSD
Aeromotice Stealth 340lph Fuel Pump (or 255 but for more power you'll have to upgrade)
Goodridge SS Brake Line Set
Test Pipes
TT Tuner Kit GT28R .86 Housing External BOV (From the GTM days but the specs offer good upgradability)
Nissan VQ37 SP Line Injector Set: 6x1050cc SP Line Saturated /High Impedance (optional but will have to upgrade stock for more power)
OS Giken Twin Plate w/ Damper Touring w/ Hard Cover w/ Upgraded Slave Cylinder (you can go cheaper here, even stick with stock and just fix the slave cylinder, you will need a new clutch if you add any more torque)
34 Row Oil Cooler + block off plate for cooler weather
CSF Radiator
AFR/Boost/Oil Psi Gauges AEM Digital Gauges
Exhaust Heat Wrap
Uprev and Tuning
Choice of catback

Suspension (aka no point in making power if you can't put it down!) Budget additional 5K or so
KWv3
Sway Bars Whiteline, stillen, hotchkiss
Front Camber Arms, Rear Camber Arms, Rear Traction Arms
Upgraded diff and engine mounts (optional)
Brake pads and fluid (carbotech XP10/8 + RBF600)
Better tires

Optional
3.33 Final Drive
IC Thermal Coating

Finally and most importantly, even if you do everything right, things can go catastrophically wrong.
Have an in case **** budget. ~6-8k of funds to at least get your Z on the road again.