Having used ACES IV in my beast for many years until it had an unfortunate trip into a chain link fence courtesy of my son, and a subsequent journey to Arizona for gradual resurrection, I was curious as to how it might work in my new daily ride. Driving an Infiniti Q50 Hybrid now, certainly not close to the RS6 but a decent ride and remarkably quick for a hybrid. I decided to put ACES in my tank today before my biweekly trip to Monterey from the Bay Area. My mileage on this 100 mile trip has been stable over the past year. This morning with ACES IV in the tank, car felt quicker with bursts, but we all know the butt dyno often lies. However, I got 2 mpg more on the trip to and from Monterey. That is amazing. For those new to the board, and perhaps with a tune that would like a bump in octane in your tank, give it a try. Dave, you were the original advocate on the board, you might wish to comment. And please, I have nothing to do with Brian and his company, and don't know what is in the mix, but I'm ordering another jug!