Would be interesting. But I am simply slapping a 10cm housing on my setup because of the extra 400cc. Drop in back pressure will hopefully bag a few kws and help handle the extra 400cc.
RB26 heads are designed around 2.6L, RB25 heads around 2.5L. They cope ok with an extra 400-500cc. Nothing wong with assuming that an RB20 couldnt handle an extra 300-400cc in displacement. I assume Nissan designed all engines around the same basic design targets for gas velocities, cylinder filling etc etc
Similar thinking is why bother building any engine for the street...why not keep throwing std engines. RB25 makes more sense on the track then street due to legality issues. Not arguing just pointing out there are so many considerations and forums are good when you get the cross section of views so people make their own informed decision.
LOL, I know whats been right for me with my car isnt right for other people.