Never noticed a difference with the standard car myself in daily use. Mines used 99.9% of the time as a commuter so normal driving mainly below 3k most the time on 30-50 roads. Unlike the mk5 were it was 98 but had 95 in brackets. VW say anything from 95ron so it was designed fine it so im not bothered.
If it was mapped and I wanted every bhp as it was my play thing then I would use it but for what mines used for.