Golfdock, any progress?
I need to update the post I started a couple of weeks ago about the same issue. Mine has an exhaust drone that I want to be rid of. I've tried a number of things to quiet the cab to no avail. I'm convinced its the muffler and the only solution is to put something different on. Adding one of those extra mufflers may work, but there are none for the Pro FX/FXT yet.
I spent a lot of money to put a hard cab on this thing only to find that I hate to drive it now because of the stupid noise. There is no good excuse for Kawasaki to put this out to market this way. I called the dealer who was going to contact Kawasaki, but no word back from them yet. I don't expect anything at this point.
I bought this machine for my wife and I to explore mountain roads around our cabin in WV. I could live with the engine noise, but the drone sucks. If not for this problem, the mule would be great for us.