High octane does not hurt (excluding 96+), but if you engine doesn't need it, you are possibly just wasting money. Stock SVTs need 91-ish. (presumably 98s a little less, 00s a little more, and 99s in the middle) They automatically retard the spark (reducing power) if the ecu determines there is predetination (knock). Many modern cars do not audibly or noticably knock. The car can detect in less than 2 revs a knock situation, and correct it in the next spark.
There is an "old car guys" tale of high octane running hotter and burning up cars. It is simply not true. It probably comes from the fact that high octane is needed for high boost / high compression situation, in which the engine inherently runs hotter.
Oh and the guy fillingup his '79 hooptie with premium (cause I want to treat my car nice), needs a visit from the wallet inspector. ("Hey, that's not the wallet inspector.")
In response to the first post, the 94 octane is a placebo. You have been fooled by the power of suggestion.
