I ordered the Takeda Intakes 5 days ago so I am hoping they get here today. I'll let you know what I think of them, I am hoping for at least 10hp. Similar Short Ram intakes like these seem to be in the 6.5 - 10hp range. However a guy on the Honda tech forum put a Takeda Short Ram on his Civic Si and grabbed 12hp from a single intake. That is pretty substantial % increase considering the car only makes about 190whp without the intake.
Takeda intake review - Honda-Tech