Can I use octane boosters in my car? Is it worth it?

Many people use them.  No concrete drawbacks or benefits have surfaced despite the heated debate that surrounds these products, making them appear similar to highly publicized 'magic products' (some of which are listed here).  As with 'magic' products, virtually no experimental data is available to either confirm or deny the claims. For more information, read the very detailed Gasoline FAQ.

The only legitimate exception to the above paragraph may be gasoline additives that incorporate the tetraethyl lead additive, or TEL. TEL was the original 'lead' in leaded gasoline, and has since been banned from pump gas in North America. TEL was used because of its anti-knock properties, which have been well documented. TEL additives can still be purchased from Kemco Oil & Chemical; their effect on DSM engines is unknown, but presumeably TEL additives will have the same problems as leaded race gas.

Formulas for do-it-yourself octane boosters have been circulating various automotive lists for a while now, including the DSM list.  Read all about them in this post from 1996 - there are some interesting 'facts' on commercially produced octane boosters as well.  GS-Xtra claims original publication of the formulas, which are also listed on in the maintenance section of the Vintage Triumph Register home page and the Team.net Scions of Lucas (SOL) Technical section on fuel and octane boost formulae - they got it from Vettenet. Mario "Porsche Killer" has added his day-glo version of the homebrew formulae here, and there used to be a link in the (now amalgamated) F-Body organization page.

Although this information obviously gets around, there are no known records of anybody actually mixing and using their own octane boosters.