Yup, I'm using two bottles of Max Boost on top of Shell 92 octane..... This is a spreadsheet I put together when I was doing my research to see what final fuel cost would be per tank. VP fuel is 8 to 12 dollars a gallon here, and we only have one E85 station.
I've got to say, I've never been a fan of octane boosters, but damn, this Royal Purple Max Boost is some pretty amazing stuff. The motor just sounds happier in all types of driving... idle, cruise, highway, WOT. I highly recommend it. The caveat with me is that I only drive my Sy around 100 miles per year, so I'm not dumping a lot of money into fuel.