i made 240whp with a portmatched AEBS intake manifold ($150)

ITBs are LAST on the list, you better make sure you have good CAMS, a GOOD header (Not a DC sports) and a ported head before you even think of buying ITBs.

and ITBs dont add TOP END POWER, that is a myth. THey CAN add top end power, but they are mainly for MIDRANGE gains and throttle response