my contribution to the fuel topic, i myself is using vpower. not for the power but more for the cleansing ability Shell offers.
if cleansing ability aside and you just wanna talk about the RON, then perhaps 95 is just right whereas 98 is just a luxury with no added purpose, or perhaps negligible effect.
I have tried shell's 95, 98 and vpower, honestly all offer similar mileage and there's no significant difference in power delivery for our skyactiv-G engine, but i'm sticking to vpower based on 2 points. Cleansing ability based on enhanced dynaflex technology and high compression ratio of 14:1. if you use 95, no doubt ecu will adjust air/temp settings to prevent knocking, but its always useful to having a higher RON to protect engine.
of cos some may argue about the price to logic issue, so just stick to what you're comfortable in..