Just installed a single Yakima rack on my pickup (q-towers) for carrying a canoe. Noticed quite an increase in noise at highway speeds without the canoe loaded. Anyone have any luck with the products to reduce the noise? One costs around 15 bucks and slips over the bar between the towers. The other is around 50 bucks, and is a larger piece that goes from the bar to the roof of the truck. Don't want to buy the lower priced one if it isn't going to make enough of a difference.