I'' admit it. I'm a wimp. I don't push my bike hard and I don't run it up to its red line.
I do ride slightly faster than the traffic around me. I do accelerate faster than most other drivers in their cages. I did average 58 mph on my 400+ mile trip up to the northern part of my State. I have ridden at speeds of 75 mph for distances of over 1 mile and I have about 2,400 miles on the odometer and my box stock torpedo muffler is not discolored at all.
The only discolored area on my exhaust pipe is around the O2 sensor and the blue/purple/yellow color extends about 7 inches down the pipe.
IMO Dirk's bike is a testament to the strength of a good design because it is obvious to me that during the "dyno break in" it was subjected to a lot of high speed wide open throttle running and damn near no cool off periods at all.
This sort of "break in" shouldn't happen to any machine.
It reminds me of what happens to your stuff when you lone it out to some stranger.