they mean you can use either a r32 rb20 ecu or a z32 vg30 ecu with a few mods (which afaik they now do before selling). the 32 ecu doesnt control vct, so you need an external controller. z32 does control vct so no extras needed.
z32 nistune is the best option for a mild r33 rb25 imo
but first, buy the turbotech mbc and wind it up to 10psi, some cars will run shit, some will be fine. so try it and see, you wont hurt anything at 10psi. just be sure to keep it under 12/13psi at higher revs, you can get away with a little more in the midrange.