I think the smallest honda used is 1.75 newer is 2.25, but i am curious to find out what the spool up on 2.5 is
after i change the cam i hope the spool up isnt below 3000rpm, otherwise ill have to try to find a 2 psi spring lol
even though power is nice, i dont want a constant high psi for daily driving

 

I have full 2.25 inch piping going into a pretty big N1 style muffler also a aftermarket resinator and i couldnt be more happy with it...it sounds very deep and has that honda sound with plenty of back pressure i love it and would reccomend that set up. I have just intake right now but will soon be ordering a obx header id go with 2.25 inch piping if your not planning on going with a turbo... if your planning to turbo i wouldnt go bigger than 2.5 inch