I have the same issue - 85KW, 2012, 86K miles. Drive unit was replaced a few years back, this is different, front, not back. Not A/C, not some "start-up" noise. At low speeds, no radio on, a distinct sound tied to acceleration. A "whirr" or electrical sound, no through the speakers. This is not the "extreme acceleration whirr" that most of the cars have - this is at normal, if not slower acceleration. I brought it up months ago during service, but I really think they didn't try to hard to duplicate it, so many other things they were focused on. When I brought it up, the answer was a "uh, yeah, I don't think they could duplicate it". Well, I duplicated it as I drove away. It has been increasing moderately, and can't be heard as easy the faster you drive - could be just from increased road noise, or it does go away. Anyone else have this issue serviced?