Hi Nick, Fuel economy, to be honest is not important to me, I'm all about ride quality, grip, and more importantly noise, In my honest opinion, it's night and day, I have no figures to back this up, But to me the steering feels more precise, the Runflats seemed to "Tramline" especially on Lane assist, Noise seems a lot better even on our Potholed roads, overall I'm more than happy and the extra expense was worth it. also bought the "Gunk" just in case. I'm told even Tyre fitters don't like Runflats. Sorry can't be much help with mileage, not everyone drives the same anyway. although I'm not Driving Miss Daisy, nor Lewis Hamilton, I'm some way between 😀. Good luck in what decision you make. 👍🏻