fit std pump and std water pump, more than adequate.
We used a std RB26 sump with removed diff and a tomei baffle only. With a greddy pump (60l per min) we had no issues for 3 years, we "upgraded" to a bigger baffled sump from a reputable engine builder and it cost us two engines (independently inspected).... swapped to an ASR and all the dramas are over.
point of story, you dont need one but if you do the only after market RWD sump we use now is the ASR (high energy) item.