I'm running 6s and a regular 66 from Shane. Keep in mind I'm at ~5500'. They definitely added some power but they are hard to drive even with the Comp turned down and not blow clouds. Don't get me wrong it can be done but if you are not patient with the right foot, you won't like it. The 66 just doesn't seem to work that well on my VP truck. I know there are lots of folks running them on the CR trucks and they work fine but on mine it's laggy. It cleans them up to a haze when it does get going but you have to baby foot it off the line or it's midnight time lol. Shane, is going to build me a 64 and we'll see if I can get something that will light a little quicker and still cool ok on top. To answer your question, yeah you can run 6s with a single but I think I liked my 4s and B1-2 better than my current setup. Nearly as fast and actually a lot quicker. They lit off that B1-2 300rpms sooner, ran cooler, and were less smokey. Of course what else would you expect right... Bottom line that is a 500+hp sweetass setup if you ask me. If we can get a turbo that will light at 1750-1800 instead of 1950-2000 and still clean the 6s up ok then maybe my opinion will change. I'm going to dyno this setup here in a couple weeks with water/meth and we'll see if it can eclipse the 600 barrier.