I would be very carefully unsung 87 in a sho, tuned or not... There is a advisory on every gas station pump claiming the "range" an octane rating can be within... Around here it's usually +/- 3, now if running 87 through your sho sounds ok, how does running 84 sound? Besides, you can't always hear detonation happening, and no matter how Breif it happens or how little load was applied to the engine while it was happening, it does damage! So just daily driving around, spirited freeway runs or showing a new SS camaro who's boss, if your running 87 in your tank it's a roll of the dice. All of this is of course my opinion, so it may be and likely is incorrect on one level or another.