Conradtan: Good summation of your 100 octane experience.
Footnote:
We run 100 in a 1978 track car w/3.2 -- only because our very well experienced Indy told us the engine will run cooler and help the top end last longer. Not spending $13K on a rebuild too soon is motivation enough. But, to put 100 in a street car may not be cost effective.
Thanks,
Ed