Beginning: When you first start to upgrade a car there are many ways to do it, , and then if you do not do it correctly you can blow your sh\t to the sky:thumbdown
Starting: If you truly want a reliable car that makes some serious power you will need to start with a engine rebuild. That head gasket is only going to take so much. If your motor is good, then that's a good start, still the head gasket might go. I would suggest a engine rebuild, with a hks 1.2 mm head gasket, ARP head studs. New coolant hoses. Keep the stock bore unless something is wrong. Stock connecting rods are fine, along with pistons, if you're really wanting more serious power go with eagle rods, and JE pistions, Cp, or probe, it all depends on what you like and how much money you have.
Refresh:
Now that your engine is complete, I think it would be easier and more cost effective for you to go with a ct-26 upgraded, there are many different wheels you can get from 50-62. It's all what you want to do. After your turbo a non restrictive exhaust will make your large turbo quite happy. :icon_bigg A Lexus AFM would be great too, so you can raise your parameters. I think it's 20% do not quote me.
Fueling:
You will need to upgrade your fuel system. if you don't good luck with a upgraded car. Rc 550's have always been good, and they keep proving they are the best. A walbro ( a real One ) if you have something better then mind go for it!. A fuel pressure regulator would also be great, set to 40, and for each pound of boost it's 1:1, ( learned that from Ij. ) if you want to add 2 psi make it 42 want to add 24 psi? make it 64 you get the point.
Tuning:
I think this is the most important part. You will need to have a good tune on your car to make sure you have everything working in sync. A AFC would work for you, it worked well for me, and I have nothing to complain about. once you get that working correctly it's always a great idea to get a Real* Wideband o2 Sensor. many people opt for AEM, Innovate, I prefer DEFI* Quite expensive but with that you get great results. Once you have all that. make sure your car is safe to drive.
Well good luck have any question, they'll be answered.