If you have a Volvo V70 XC, the turbo does in fact feel noticeably better from 87 to 89, and again from 89 to 91. 93 and 94 were almost impossible to feel gain over 91 octane. This car was a "low-pressure turbo." And yes, you could run it on 87. It would act fine. It would simply "feel faster" on the octanes I described.
I know this from having two.. one in Massachusetts (hello, everyone,) and getting gas from the Sunoco at Braintree Circle, and another in NJ - A silver 1999 that I got for free, had in NJ, and that BITOG does not know about.
Put in for points of reference to the discussion about octane.