Originally Posted by Kingtal0n

It doesn't matter how much boost you are using. Boost pressure of 18psi has no relevance to combustion pressure which could be over 1000psi.

Stock internals I would stay under 450rwhp dynojet using E85
All sr20det engines need cam upgrade. It fixes the high rpm volumetric efficiency the engine is capable of, more power with less boost pressure. The reason we like less boost pressure is because its less risk blowing apart the plumbing/clamps, not because it might blow the engine or gaskets. What blows the engine up is hot air, which high boost pressure gets blamed for, and also boost leaks, which causes hot iat AND high EGT, which again high boost pressure gets blamed for. And finally if you exceed the stress that factory parts can handle, something can bend or break. Engine torque is provided by an integral of pressure over some crankshaft radii, so for example you can generate a lot of torque with a sudden push, or the same amount of torque by pushing gently for a longer time while the crankshaft turns. So it could be safe for example to use 500ft*lbs of torque on a factory rod if the push is done over a long time frame of rotation of the crankshaft (using cold temperature and high octane fuel this is what happens) but you couldn't make the same amount of torque using a high temperature and lower octane fuel because the pressure will spike before the crankshaft has a chance to move the piston out of the way (the reaction happens too quickly). So it really comes down to control, tuning, awareness, how much torque the bottom end will handle.

E85 is the ideal choice for cast piston engines. I Would say camshaft upgrade, and focus on the turbine/exhaust (make sure the exhaust is as free flowing as possible). This will maximize the effects of boost pressure on the intake side and minimize the efficiency losses and heating on the exhaust side. That turbo is tiny for that engine so it won't take much. I wouldn't bother messing with nickles and dimes at this point (wastegates/intakes/minor bs trying to gain 20hp). A cam upgrade is worth 20-30% power for example (80hp~), if the turbo can support the flow rate. if you max the turbo and want more power you simply use a larger turbo.