There was a long discussion on this subject not that long ago in this forum. There have been quite a few people that have tried 100LL, myself included, that haven't seen the benefit. To the contrary, the lead build up on the plugs is quite detrimental regardless of mixture settings. In some climates there has been a small benefit to using 100 octane racing gas (not low lead aviation) to help maintain a higher CHT in extremely cold weather or for delaying detonation in extremely hot weather. Significant power gains have not been noted for the most part.

Essentially it comes down to how much you want to spend on gas and plugs. Like spending a lot more for exotic fuels and replace/clean plugs a lot more often, then the 100LL is just the ticket. If all you want to do is spend a lot more, then the 100 octane racing fuel is for you. There does not seem to be any reason to use anything different from what you can obtain from any one of the pumps at the local gas stations.