269 km/h (167 mph) on the GPS, 5th gear, bags on, stock bike ('08) except the Givi windscreen, which does brake her a little. It was in the new 3 lanes section of the A8 from Munich to Stuttgart. Bike has 50000 miles on it, almost broken in.
While chasing a buddy that was on a BMW S1000RR (said chasing, not catching), I did hit the rev limiter in 5th gear while tucked behind the stock shield of my 2011 Black, with a 50 profile rear tire. That was before I had GPS, so can't document exact speed. I seem to recall the speedo in the 160-162 range, but wasn't really watching that closely. The road ahead seemed like it needed my attention moreso than the speedo. Based on later calculations after I got the GPS, I'd say I was in the 153-155 range. This was on a fairly long, straight, rural state highway in North Central Texas. (Plus, he was well ahead of me, although still in sight, running a radar detector.)
Never been over 135 since.
The C14 will do 17.5 mph every 1000 rpm in 5th gear. I'm not sure at what rpms this engine cuts in the >'10 models, but mine cuts at (indicated) 10500 rpm. If you use real (98%) tire radius and gear ratios, that means that in 5th, in '08 and '09 models, she'd have to be doing 183 mph, which she simply can't.
So, if your bike cut at 155 mph in 5th, she was doing about 9000 rpm and the limiter was implanted
German magazines keep quoting 246 km/h (154 mph) as top speed from >'10 on.