Since BigB is talking racecar only, I would think the race fuel is the right answer.
For those of us who do the street/strip thing, this article by Eric Douthitt makes a whole lot of sense and I know 2 guys here in the Phoenix area who are using his Toluene formula with success:
Octane article
Note that in the article he also talks about "AV Gas" and only recommends its use in a narrow set of circumstances. (Race only car of about 11:1 compression and specifically jetted for the avgas.)
"Nothing Beats an Ol' Goat..."
