I'm extremely interested in buying a Venture as well. Years ago I had a 96 Royal Star that I wish I would have kept. I had a set of four by four pipes on it that sounded better than all the Harleys I had. Of course, I never heard a whine on that bike, but I did read where others had.
Years later now, and one thing I ran across here was a post by a current Venture owner who installed the V-Max differential and noted that he no longer had a whine.
I don't know how many of you guys have changed out those differentials (I did on my 96 and it really made a huge difference in power characteristics) and if so, what kind of effect did it have on these whine/scream issues? I also had a V-Max after the 96' RS and I never once had an issue with the whine. There were other issues like holding on for dear life, but that's another story.