You will need
Fuel pump-wally 255 maybe a 400
injectors- id1000ccs would be the best choice but 750+ may work
new clutch<you better or you will anyways
Solid location to get your car tuned
Gauges such as Air/fuel and boost especially the A/F will be required!
You may have to consider going E-85 if you want a real solid 400whp out of those turbos safely.
If you didn't already know alot of this information you need to do alot more research or find a solid tuner call him up and talk to him to find out what you need for your power goals for what you plan on doing with the car, build it how you guys decided to go and take it to him to let him work his magic.