I've used Boostane before and currently use Lubegard products in my trans and engine.
My car is normally tuned to run Ethanol but at one time I was experiencing delays in getting product (no pump E85 where I live). I tried the Boostane in hopes I could continue to keep my boost turned up while I waited for the next shipment of Ethanol to come in. The change in fuels involved some retuning of course but bottom line is, it does work. Unlike most over-the-counter octane boosters. I believe Hartline Performance has a thread somewhere on here where they did testing and subsequently became a distributor for the product. I eventually switched back to Ethanol because my car just runs better on it but I would not hesitate to use it again in a pinch.
Likewise, the Lubegard trans and engine oil additives are good products as well. I wouldn't say the same for many other similar products.