The baffles come out and yes, there is a slight change in sound. They are only about 2 inches long...I pulled mine out a long time ago, but now run the single Akra in either the low or high position. I was able to source the S pipe for the high exhaust and everyone at Eurocycles in Tampa really liked the look and sound of it.If you watch this official BMW video on the NineT you'll see how the guys are unscrewing a round restrictor (?) from the standard exhaust.
SOULFUEL - YouTube
I wonder if this allows some sound modification of the stock exhaust similar to some aftermarkets pipes for H-D's?
A handful of bolts and less than 30 minutes, I can change my exhaust from the stock, to the single low, or the high pipe. It's nice to have choices. If you go the the Garage tab and look for the one titled "My Toys" I have posted pictures of my bike in all three configurations and my home made tail tidy which is still a work in progress. Speaking of which, I need to get off this stupid computer and go out to the garage and get to modifying the tail tidy now...later...