You are comparing 98RON with E85, yes?
Dude, maths is something that's superfluous, or "not-going-to-assist" in this instance.
OMFG.
Mate I don't get your point and frankly don't know why you keep posting in here.
You originally said this "So for 30% extra cost (allowing for equal price at pump, which it WILL be) you get a staggering 4% increase in power! Top stuff indeed!"
I pointed out to you that in fact E85 is 30% cheaper which means that if you use 30% more then you will be paying the same at the pump and you get a nice little power increase.
Most people get their car tuned to 98 anyway, so I was raising the point that if you have a series 2 (or E85 compatible car), then why not? - this is what we are discussing here.
We do not need someone sarcastically flaming the idea with incorrect assumed facts, please do not comment unless you want to make a sensible contribution.
This actually goes for any post in this forum...