The octane boosters that do work are only effective for about 2 #s (i.e. 93 boosts to 95) when mixed at 1 oz per gallon. Most of the stuff on the parts shelves doesn't work well enough to bother with.

Stuff that's been tested independently for that 2-point improvement includes Amsoil's and the "race blend" NOS brand. There may be others that will get you 1-1.5 points, but I can't say which ones at the moment 'cuz all my research notes are on another 'puter.

BTW, 104+ used to actually do something. However, it's been reformulated into something that's now about as effective as "diaper squeezings" for some reason.