Well your emmissions and power might get a bit worse. Would it be noticible? I don't have a clue. The higher the octane rating the slower the burn. So if the timing is already tuned in at max ECU advance with 87 octane to acheive the most efficient transfer of energy it won't advance further with 94. So the point of peak pressure will actually fall too late having an effect on the intended efficiency. Slower burn rate also means less burned in the given period of time which I would assume leads to higher emmissions.

Pinging, knock and detonation are all the same.