I have an 09 Si 4 door I want to play with, have the cold air intake and working on the exhaust, I'm thinking magnaflow and turbo in the not to distant future. My first question is will the K20 handle 8-12 lbs of boost without internal upgrades? Also will the stock injectors, with the right mapping handle it, or should I replace the injectors

 

psi means absolutely nothing. 8psi through a mcd's straw will be a different amount of air when compared to 8psi from a turbo.

Figure out how much money you want to spend, and how much power you want. Otherwise, you are wasting money and time. For example, that intake you installed will need to be removed and replaced with intercooler piping once you are turbocharged.

I am sure the K20 block and hold 300whp no problems, but I do not have personal experience with this. Stock injectors will most likely need to be upgraded.