Vtec is good when you want to make power through the whole RPM range, ie 1500-8500 or whatever. When your racing though you only see low RPM's for a very minimal amount of time or in the case of road racing never. So if you can lighten up the valve train and throw in some roller rockers gaining back some horsepower taken by moving the extra weight of the stock setup and have less friction
good. All you sacrifice is a little on the lower end that you arnt really going to miss. On the street though the car would probably be sluggish as hell on the low end though, Just an assumption though