either way, i threw in $20 worth yesterday after work (4 gallons!!!) and it felt a bit quicker after going through a couple drive cycles, thinking maybe it took a minuite for the computer to realize what was going on...or maybe it was just me. who cares, 100 or 93 the S still rips.

 

it dose take a bit for the ecu to make adjustments

 

well i pay 8$ a gal. for my race fuel "Leaded"

 

I use Shell´s V-power 99 octane (unleaded) in my car. I have read a test where they compered 95-99 on a 997 carerra S, I dont remebmer the exact result but I definatelly got some extra horsepowers with the 99.
I dig it out and get back with the exact result.........
Btw...98 octane minimum according to my manual.