Not overkill at all in my opinion. I doubt the lag is even noticeable between the two. There is not that much more volume of space to pressurize. I would do the VRSF race IC on anything other than stock turbos personally. I have not seen any direct comparison between the two. If you did not already have the race IC then sure the comp might be a bit more appropriate but the extra cost for the race is minimal and you get more headroom and cooling with the race. Probably not worth the hassle of selling the race and buying the comp...but I am sure the race would sell quickly.
@Jeffman If you currently happy with the AIT rise you get now on a multi gear pull then keep it. I had the Helix on my car when I was on stock twins and it was great. It is a very high quality well manufactured product. Instead of spending the money twice and buying the VRSF race, I would vote add meth. You will get decent cooling boost and octane upgrade for the same price as the race IC. I doubt the helix is a restriction unlike the stock IC would be. So meth would get you extra cooling, more octane, and once you tune for it, more H Ps. A win win.