To build your car correctly the first time is still going to take alot of money. Even if you get lucky and find some some cheaper parts and get the setup together..eventually you'll turn up the boost and we all know what happens then. So, I suggest to piece together a custom turbo for your car, build the bottom end and take the time to do everything right. Everything with a turbo cost some $$$. 99B16Si has a nice setup w/ the t3/t4 and can beat the best of 'em. I'm going turbo as well...not with the same setup as him, but I am slowly figuring out what all i need before i buy it and how much power its gonna give me.

Just so you have an idea about the GReddy Turbo kit on your Si since you posted earlier about it ...
lets say GReddy Turbo TD05H-18G, and you wanted to run low psi...so lets say 5-7 psi, For fuel enrichment your going with four 310cc low impedance injectors and FCU (fuel control unit). You are looking at 220.1 to the wheels. If you go with an intercooler (which is optional with this kit) you'll get 244.3 to the wheels. Price = $3149.

Be very detail oriented with choosing your setup...i wouldnt suggest being half ass. If you want it to last awhile just take the time (and the money of course) to do it right