FWIW & IMHO:
Virtually all octane boosters contain a substitute for lead called MTBE, or something similiar, and that is what fries your oxygen sensor, and probably does not do the cat, if you are running one, any good either. At one time all of the manufacturers of such products carried a notation on their warning label. The last couple of years most/ a lot of manufactureres have removed the notation from their warning label regarding MTBE, I suspect due to lagging sales. At one time, "Trick" Racing gas made a oxygen booster for non-leaded cars. Great stuff, but probably no longer available. I have not seen a can of that stuff for about 15 years.
Also be advised, that when the can says will or can raise your octane level 10 points, a point is actually only equal to 1/10 of an octane. Very small gain for the expense. Turns your plugs orange, too, which I don't think that in itself has been determined to be harmful to your motor, probably not doing it any real good. Race gas blending, alcohol injection, Zylene, or toulene seem to be most popular choices for octane boost. My $.02 worth before taxes, too.
