there is no set number of HP that you will get when you go LS/VTEC. There are difrent factors that determine the HP. How well the engine was taken car of, what head you put on it, what parts you have on it already. so just saying that i will get an extra 45 hp when i bolt on this head is an estimate and not a fact. you will get more HP if you bolt on a type R head than a GSR head, I dont know the diffrences between the ITR and CTR heads, but i cant imagine they are that diffrent. If you have any more questions just ask about LS/VTEC or about engines in general.