[YOUTUBE]
https://www.youtube.com/watch?v=v0PvAudkAuw[/YOUTUBE]
You may want to wear headphones to hear it. It's the pulsating/"chuffing" noise. Only happens between 20-45~mph when accelerating even with the tiniest amount of throttle. Noise stops completely as soon as you let off the pedal. The frequency of the pulsating follows road speed, not engine rpm.
You can kinda feel the pulsating in the steering wheel
Sounds like it's coming from deep within the front of the car.
G'box fluid was changed about 5000 miles ago, engine oil about 100 miles ago.