Wont cause any damage to the motor but it wont make a difference really. Only 2 reasons to use that higher octaine gas- to ward off pre-ignition (due to several reasons but include high compression pressures from say boost, or a 12.5:1 NA build) or to allow you to run a very advanced ignition timing map.
Hi, my name is 95BlkMax, and I am a Boostaholic
"DANGER TO MANIFOLD!!!!" O_o!