I can't find any mention of a knock sensor in the '08 service manual. If these engines don't have any, people should realize that there may be trade offs when using high performance timing curves.
The factory is worried about their warranty exposure. Put enough vehicles out there and sooner or later someone is going to load one up to the max, on a hot day, with a bad batch of gas and redline it for some length of time. The factory doesn't want detonation under any circumstances. Since the Teryx is, what, twice as heavy as a quad, timing can't be as aggressive as it can in the lighter, easier to accelerate vehicle.
And then there is NOX emissions, which are worsened by advanced timing, and there is no cat to clean them up.
All of which means there is a big margin of safety to exploit. The question is, how much of the margin of safety do you want to use up? Will you hear the engine knocking with that loud exhaust and all the noise going on at 65 MPH when all you're focused on is beating that other guy?
There's also a certain amount of useful work built into every engine before it wears out. How quickly do you want to use this up? There's reasons engines that generate racing levels of HP last only one race.
My stock FI starts easily, idles sweetly, doesn't foul plugs, gets good mileage, runs strong, all on crappy CA regular. More HP is great, but only if I get to keep all of the above. So I'm in no hurry to change things until the pros can give me guarantees.
My dream engine would be built like a Caddy or Lincoln engine from the sixties. Lots of displacement, moderately high compression, conservatively timed and cammed. I'm not interested in winning races, just having lots of easy starting, smooth running, easy to control, quiet, reliable, long lasting, load hauling power at all reasonable speeds over all kinds of terrain.
Kawasaki got it pretty close. The only shame is that they didn't give us a little more compression. Even in California we have 91 octane.