You are right about the detonation and preignition, which aretwo totally different things.
The ROTO also requires premium fuel. I am 100% sure about that, unless ROTO makes special engines for the US market.
In Europe, your crappy low octane stuff is not available, even if you want to get it.
We have as lowest Euro leadfree 95 octane, which is RON. (research octane) PON (pump octane) is typically four points lower, but in good quality fuel the difference is less.
ROTO, which followed the MVVS success line, also has it's compression ratio maxed out for best performance on the available fuel, which is 91 PON. IIRC, they also ask for premium fuel in their manual.