I find all gas to be the same ... however I seem to get better economy by staying with the same brand ... I beleive it is becasue most gas is the same but each company uses a unique blend of cleaning additives which when used over and over get better consistancy ...however not by much

 

I like Exxon Mobil

yes you will notice things work much better when you switch from 89-93 to answer your question. Also, I cant say for sure but neither can anyone unless we get official word on the 91 vs 93+ performance, I think it will make a diff past 91 someone should ask GM performance..

Anyone that puts less than 91 in their SS/SC is a retard IMO... Chevy reccomends 91 and say if you need to you can put a lower grade... even if it were a $.15 cent diff in price (about $1.75 a tank when just above empty and below 1/4) why wouldnt you do it????
You buy a $25k performance car and you wont spend the extra buck 50 on gas every tank??? That has to be the dumbest thing I haev ever heard... and you get betetr gas milage when you use the right Octane