this is the new vtec (ivtec) which came out in 2002 i believe, with the rsx type s and the new civic si, but there is still a diffrence in those two. The "old vtec" was still something you could feel on engines that were perfomance minded, such as integra's and preludes and i think civic si's, but not sure about the si's. But the new si's are fuel effiecent minded, so there ivtec is not that noticable, but the rsx is. So even with the new ivtec is variable in being noticable or not. Get what i'm saying or am I just being confusing? Oh well, I'm sure somebody else will explain it better.