I'm using the RaceChip GTS Black in my 3.3 Stinger. I was fortunate to come across a gas station on my commute to work that sells 94, 96, 98, 100, and 101. I filled up with 94 and put my chip in Race mode and car in Sport. Felt like more power to me, but then maybe it was a self-fulfilling prophecy and this was the first time I tried the chip in Race mode as RaceChip states the octane should be between 93-98. Any harm with using Race mode with 91? I suspect not, it's just that the hp gains will not be as much. Looking for feedback regarding using higher octane gas with a pnp chip and were the performance gains noticeable.