If I read you correctly Centaurus, are you implying that if you nail the instruments (ie pitch), you won't get the illusion in a C210, but you would/could in something faster?
G'day CS,
I imagine he's just referring to the root cause of the illusion, ie longitudinal acceleration fooling the body into feeling that the real gravity vector is not pulling straight down, but from somewhere down and behind you, so you feel like you're falling over backwards and want to push to compensate.
More acceleration, worse illusion. I think it would still be possible to experience it to some degree even with moderate acceleration, though - haven't seen any figures to refer to a minimum rate to trigger an onset.