Are any of you using an RBC intake manifold? (vs. PRB that comes stock on the k20a2) Here is a comparison: RBC on the left... The RBC is stock for US Civic Si. The 15hp increase, pretty substantiated claims are out there from what I have read and discussed with my tuner. I think it will fit the custom box/panel (behind seat) but not sure about the space around the fuel cell.