Ok, I thought Id post how to match a compressor to your engine. All of this info is taken from part x of suck squish bang blow in the sept. 2001 issue of SCC.
First you need to figure out the pressure ratio. What basically determine this is what boost pressure you will run. This number will be plotted on the Y axis of the compressor map. To find PR: Pr=boost pressure (lets use 10)+14.7(atmospheric pressure)+1.5(intercooler pressure drop), then divide all that by 14.7. so, (10+14.7+1.5)/14.7=1.7823.
Now we have to find out the the Intake air density, or Di. Di is equal to: (boost pressure+atmospheric pressure)/(R constant x 12 x (460+intake temp). R is equal to 53.3. so, Di=(10+14.7)/(53.3x12x(460+130)=.000065454. Just use 130 as the intake temp.
From that number we need to find out the Mass Flow Rate, or MF. This is how much the engine will flow at x rpm. You will need to use this equation a few times using different rpms, ranging from 4000 to 7500. We will use 7500 in the example. So, Mf=DI(what we just did) x displacment in CI x (rpm/2)xvolumetric efficency. the displacment of an sr20 in CI is about 122, and you can just use .9 for volumetric efficency. So, Mf=.000065454 x 122 x (7500/2) x .9=26.951.
Almost done. One more equation. We need to find Corrected Mass Flow, or CMF. CMF= (1/(14.7/13.95))xMF. so, CMF=26.951 x (1/(14.7/13.95))=25.576. Ok, No more math. Just do that again with some different rpms, and try different boost pressures too. You just plot the pr and the cmf on the compressor map. Some compressor maps can be found here,http://www.turboneticsinc.com/comp_maps/fig1.html .
I hope I got all that info right...

-Mike