The only germane data point I can offer is that I tried a stock Carver M500 with my RS-II, and it was immediately clear that better amplification would be needed. Currently I am running Classé monoblocks that are up to the task, but I can't say they have too much power.
I'm familiar with Nelion but I have no direct experience with their mods. Looking at the power claims they make though, I would venture that they perpetuate Bob Carver's legacy in more ways than one 😀
Based on your musical preferences and expected listening sound levels, your modified Carver will most likely drive your speakers to your satisfaction. Enjoy!