Think about it: the HP2 Sport.An exhaust flap in front of the muffler is actuated by an electronically controlled servo-motor via a cable. This constantly adjusts the internal diameter of the exhaust system to suit engine revs and ensures good low to mid-range performance for a linear output all the way to the rev limiter.
It's not a milquetoast system.
This issue of this magazine, BTW, is from when it was a German publication, i.e. before takeover by our wonderful friend in Tucson.
The K1300S has it, too.