Just a thought here. I noticed that the wine on my 06 venture i had, got much worse if you were running the intercom with the passenger. The mics picks the wine up and the higher the intercom is turned up the louder it gets. Just take you bike out if you were using the intercom and turn it off the noise almost goes away. I ran my intercom as low as I could to just here the better half behind.
Just my thought and something to think about. I traveled all across the USA and Canada on my 06 and had the I basket install and it did get better at highway speed but still had it at low speeds. per the comments from the factory rep that put the I basket in mine he stated that the wine will always be there but he could move it with different baskets so I told him I did not want mine to wine at highway speed and he did get 90 % of it gone from 55 to 75 MPH but moved it to below 50 but then you can change gears to make it better.
Just my 2 cents
Good luck