Now, 350hp isn't an unattainable number. It's pretty easy with a large-ish turbo like mine, the trick is to get the smallest turbo you can possibly find to meet your power goal so you have more area under the curve ie: more horsepower and torque sooner. You're going to want to lay everything out beforehand, and ensure you have a daily driver while you spend some time getting it working right.
Please take a look at my thread for an example of the parts not to cheap out on. Here's a list of what you should be spendy on:
Injectors
Fuel Pressure Regulator
Fuel Filter
Turbo
Turbo
exhaust Manifold
MAP sensor
Blow off valve
Wastegate
Tune
Rods
Pistons
Breather/Catch-can Setup
Traction Bar
Engine Mounts
You're going to want to buy these rods and pistons:
SpeedFactory No-Notch H-Beam Long Rod and Vitara Piston Combo D16 - Connecting Rods - Engine Block Parts - Engine | SpeedFactory Racing
And then you're going to want to buy a good
fuel pressure regulator, good injectors, and get a good tune to go with the $2500 in parts you're going to throw at your '92 to make it fast.
It's not just the engine parts, but the systems that support the engine and transmission. I've got just a hair over $6k into my car now, including purchase price, title, registration, etc and it ran a 11.2s @127mph back when I only had just over $3k into it.
But, with that little money into it, I kept breaking things, blowing things, etc. My buddy jokes with me all the time that while my car will get me there quick, it won't get me back. :/ So, I put about $3k more into it, and now it'll be solid.