I use the Triumph Roadster screen on the SM and appreciate it every time I clean the bugs from it. Not too much buffeting, and protection from sand, dirt, or what ever may fly up from the road. About a month ago while in the N Ga mountains I was "dived bombed" by a large bird and was glad to have the screen to hide behind.
The large windshield has another advantage, it provides enough wind drag to allow Americas a chance to keep up with the SpeedMasters
