Well, we're coming up on a month since the last sound post, are we not?
If Kaz can't find an hour in a month to knock out a little more of the sound story, even if it needs to continue into part 4, I don't hold high hopes that we'll ever see much information out of the Pitstop. It's clearly not that important to them. Maybe we'll see the end of the sound question, maybe not. But expecting anything more beyond that seems like folly.
I suspect Pitstop was a nice idea, that happened to coincide with the Nurburgring so they tried to kill two birds with one stone. They got the information about the Nurburgring out OK, but I think they missed the second bird.
That's the story of Polyphony in recent years. Tried, but then something happened along the way and it didn't quite make it. Sorry.