I have read this string with interest. My 2012 Golf has a very noticeable vibration between 28-45 MPH with mild to heavy throttle. The vibration mabifests itself only when traveling straight. In a turn the vibration diminishes to the background movements of the vehicle.
So far I have balanced then switched wheels without much change. The dealer put in a new drive axle which may have helped some. At first the dealer claimed they could not dupicate until we went for a ride. I knw this 10,000 mile car so well that I can reproduce the vibration at will. Most days I just drive around it, ie soft peddle through the zone and drive on. It is most noticeable on the on-ramp to an expressway.
Car goes back to the dealer this weekend for an extended stay. Too bad I like the car but will not accept it as is and have said as much to the dealer.