"Octane booster", "race fuel concentrate", whatever you want to call it, I know there are a lot of choices out there, some that work and some that are worthless. I've used them in the past, but have tried to not rely on them. I don't like the MMT deposits (the orange "rust" on the plugs & chambers), but MMT is one of the additives that does improve the AKI (Anti-Knock Index).

I've Google'd the topic quite a bit over the years and it's tough to get consistent information, even about the same product as tested by different people. It's also (kind of?) interesting how some of the products might improve the AKI, but it doesn't translate into an improvement in power. Certain ones (e.g, Boostane, Torco) have shown small improvements in power as "pour in" tests, and additional improvements by raising the AKI and enabling a more aggressive tune.

IIRC, Torco Accelerator used to be available in a leaded and unleaded formula, but I can't find anything about the leaded version any longer. I think that's now called blending 110 leaded race fuel.

Like I'd first mentioned, I'd prefer to be able to mix a "real" race fuel w/ pump gas as the normal fuel fill. But I do need an alternative for when that doesn't work out.