I'm getting closed to an xB purchase and noticed (during the test drive) that there was a dash buzz at about 4K and a pop that occured right in front of the dash when lifting off the go pedal while accelerating.

There is a TSB on the dash but I'm not sure about the popping. I did see a TSB on the cowl piece in front of the windshield. That could have been the source, not sure.

Has anybody heard this or had it serviced? What gives?

TIA

Heard the buzz before.
Not the pop.
How can you lift off,of the go pedal,while accelerating?
when lifting off the go pedal while accelerating
Give us some more detail under what conditions it happens.
I have never heard it before.

Simply accelerating, then letting up on the pedal to slow down--that's when the pop outside the passenger compartement happened (twice). It's like the drivetrain might have been rubberbanding or a constant velocity joint poppping.