if its a type R head then, yes there is some advantage, but probably not enough to be worth the price. you would be better off just upgrading the b16 head with better cams and valvetrain. it could potentially make more power than a stock ITR head for similar money (since most nice itr complete heads are $800+). if the b18c head is from a jdm gsr motor then there would be no point in doing it at all, just upgrade your b16 head. keep in mind whether swapping a itr head on or upgrading your b16 head, that the setup will need to be tuned to be safe and make the power gains you want.