What kind of SC are you running? Roots or whipple? Maybe even centrifugal? THE person to ask these kinds of questions is Tony D, I believe that his job entails industrial application of air compressors. The thing you have to remember though, the correlation between compression, flow, and compressor speed are not linear, and depending on the blower in question have different values as well as different efficiencies.
The Injector thing is a different idea entirely, it all depends on what your expectations are for horsepower and what SC you're running. Generally though MFG's shoot for about 80% duty cycle in their injectors (though some cars like the WRX Sti and Evo's are running pretty maxed out injectors from the factory) so you have a little room to grow, but not long before you'll need to upgrade. Luckily, turbo cars have bigger injectors and you can probably find Injectors from a turbo Supra (the us spec, I'm not sure if the euro car is US Or Japanese spec), RX-7, or in europe probably the C20 Turbo injectors and have it made.