As said, the ecu does it job of utilising the lower ron fuel by "de-tuning" itself, but the owner clearly isnt bothered about the ill effects this has so I wouldnt bother. Many other careful considerate sellers out there.

 

If he's scrimping and saving on that, what else is he doing to save money? Either that or he's not an enthusiast and doesn't know about these cars. As said, plenty of other cars to be had .