It's 100% exhaust overrun. First time I experienced it was in "Normal" exhaust mode while lifting off the throttle on an incline, and I thought something broke because it was unexpected 
I like it. Can't really induce it the same way you can on an F-Type or some BMWs, but "burble tunes" are so ******* annoying and overplayed at this point that I'm more than okay with it being occasional.
I like it. Can't really induce it the same way you can on an F-Type or some BMWs, but "burble tunes" are so ******* annoying and overplayed at this point that I'm more than okay with it being occasional.