Hi all, I'm considering the purchase of a new Tow N Go. I love the sound, but my wife is concerned that the exhaust will be too loud and/or an annoying drone when towing a travel trailer on the highway for hours. Not towing, she's happy that it's quiet at highway speeds. But I can't replicate towing in a test drive. Can anyone comment on this? Is it quiet on flat highways (think I-80 through Nebraska)? Does it just get loud when pulling in the mountains? Thanks!