I did actually say that engines that have to retard their timing to run on 95 will run at their intended full power on 97, so I'm glad you agree. As aforementioned, that isn't an improvement in power but is simply allowing those units to operate optimally

Cetane is a critical element to consider with compression ignition, which is why I wrote "...so questions over octane don't apply.". Once again, I'm glad you agree.

Please feel free to direct me to some research which is both properly scientific and independent - you indicate there are many, yet have failed ro link to a single one. There's plenty of magazine guff, and consumer groups, TV programmes, YouTube carriers et al, but I've yet to to see any credible, properly objective scientific testing that proves any benefit. There wasn't any when I was studying the subject postgrad, and I'm not aware of any since.