Took a look back through your old posts.
Main things you already have are Clutch, Brakes and Exhaust.
So you have a decent base to work from. I would hold off the engine build for now.. Work with the standard engine and turbo for now...
Things to look into
Induction
Induction Filter
BOV - Blow off Valve / Dump Valve
Denso IK27 Spark Plugs
Front Mount Intercooler Kit
The Mongoose Exhaust that you have now will be fine!
Management
Boost Controller of choice @ 1.2bar
Walbro 225L Fuel Pump
Check the AFR across the rev range. You may find that the ECU compensates enough to run this boost without the need for and extra fuel management.
Engine & Turbo
I would leave it standard for now to be honest.
Brakes
Brembo 4POT's you have now are perfect for you!
Suspension
The standard suspension with some Eibach springs may be your best option as far as actual shock absorbers go. You can look into the various coilovers but unless you are taking it out on track and will put up with bumpy ride for daily use then go with he above suggestion.
To improve the handling you can play with the geometry to improve the turn in and grip. Also look at the Whiteline Handling Kit. Will really help a setup like yours!
Also Front, Rear and Lower strut braces will help keep your car more stable through the bends and helps reduce understeer by allowing less flex in the chasis.
Drivetrain
Nismo clutch you have will be fine for 1.2bar.
I assume you are using the organic plates. This takes some strain off the gearbox which again will be fine with that sort of power. Use Redline MT90 Gearbox oil. Its a very good shock resistant oil which will help the life of your box
Other things to consider...
Front Mount Oil Cooler Kit
Twin Core Aluminium Rad
Piggyback or Standalone ECU
With all that you will have a very reliable and well sorted 320bhp+ car. To be honest you will find that very fast.
To go further will mean new turbo, engine build, gearbox, management, injectors, etc and will really start to cost mega bucks!
Hope that guides you a little to a decent goal
Rishi