If you can find yourself living with the noise., you will find that the RTV's performance is so much better with the OEM, ROPS high rise system, your engine can breathe so much better, myself and many others has notice the difference !!!!
The Kubota engine in the RTV's, do take in much air, that might be what you are hearing, it gobbling it all up to run better for you !!!!!!!!
Do this test to show how much noise reduction the sliding back glass does take away from the ROPS high rise system, CUT yourself a piece of cardboard, or something simular, of the WHOLE size of your back section where the glass goes. Snug it up really good and run it with your high rise on, you will see how much reduction you get. It does cut down on the noise some. Personally, I don't even know it's back there now with the back glass. Really only hear it when you start slowing down really quickly, and that's the engine brake is doing it 's job ~~~~~ Sounds like a Jacob's brake on a 18-wheeler ~~~~
~~~~~~~~~~~~~~~ ~~~~~~ Two Guns ~~~~~~
TWO GUNS SWAMPS OF LOUISIANA