So the Skid Factory have done some dyno testing on E10 v 98RON fuel with interesting results.

I've been running E10 in my L322 M62 V8 nearly since the start of ownership 4 years ago. It's my work car so I do some KMs in it. I did the comparison of 95 v 98 v E10 and found my car does not give a toss which ones of these I put in it. They all perform the same.

Link to the video Tuning Our Car on E10 to BEAT FUEL PRICES $$$ - YouTube