to explain the octane level the higher the octane level the higher the temperature the fuel can reach before self detonation caused by the heat from the compression of the air in the fuel air/mix due to the low octane level of unleaded the fuel can detonate before the spark plug ignites it causing pre det which is bad for your engine the knock sensor detects these pre dets and the ecu adjusts the fueling causing your engine to not perform as it should hence y its better for our cars to use v-power my friend came to me said his s3 was running shit he was running standed unleaded told him to change to v-power few days later he came bk to me said it was running amazing couldnt believe the improvements