I have to agree a little bit on the noise though. While training with slow riders (i'm slow, but even i pass people) you have to be really carefull because they don't notice you comming up. I have that less on my 2 stroke. The 4 strokes really don't hear you although the guys riding enduro bikes should be able to. But the 2 strokes (especially enduro's) can hear you. However their brains don't connect the Stark noise with an incomming bike yet. Can't blame them either. I hear it al the time so i immidetly hear and recognize a bike incomming, but their brain is not trained at it yet. I think that will improve over time, but for now Starks are still an odity.
But last year i was mostly the only one at a track with +- 100 people, this year i'm seldom alone and plenty of times there are around 5 Starks. An with that you start to see more people notice you when you come up from behind.
I think, speaking for the Netherlands, 2 and 4 stroke noise have to come down. So many complains and restrains on MX tracks. And a very decent workable solution is there. Enduro mufflers are way quiter. If the Importers of all OEM's stick their head together and at least sell the bikes new with an Enduro muffler they all have the same loss of power. And to be honest, most people can really do without the last 3HP.
Also tracks can come up with it being mandatory. Our small local track is considering this. Offcourse people are complaining about it being expensive. But somehow those show up with new bikes every other year that go to the suspension tuner before riding their first meter.
And well, if everybody drops about 3-5 dB, the ''Safety issue'' is more or less gone as well.