Hey dude, to clarify:
SR20, KA24 ARE side feeds, as for the RB-series, only RB25DET uses side-feed high impedance 370cc injectors, the RB20DET uses top feed high impedance 270cc injectors while the RB26DETT uses low impedance 440cc injectors. It is said that the RB20 can accommodate the RB26 low impedance injectors with the use of the RB26 injector resistor pack. I have also heard that the RB25DET side feed injectors are interchangeable with the SR20DET.
Hope this helps.