I have heard this "jet engine" noise on my car from day one under light throttle. I love it. It reminds me that I am driving something very special. My favorite sound is the re-gen whine while braking. Lots of unusual sounds coming from this car all the time. For instance, in the garage after about a minute. When opening the drivers door after it has been sitting for a while, etc. Adds to the experience in my book.