95 vs 98
I hadn't thought of using 98 at all as I have an account with Shell who in my area only do 91 & 95. I have been running my VE SSV on 95 for 6 months.
Did a trip down country and no Shell stations around so filled up at BP on 98 not expecting anything different.
I was very surprised when after a few ks the car seemed to me to have a bit more pep with cleaner throttle responses and smoother running, particularly when doing some "spirited" driving.
I don't know that it was any more powerful, it just seemed smother and a bit more agile.
Perhaps the previous owner had run it on and had it tuned for 98 or perhaps the 6ltr V8 just likes a slightly higher octane, I don't know.
Its all gut feeling with no figures at all to back it up but what made it interesting was that I was not expecting any change so had no preconceived ideas of what it would do.
I enjoyed the smoother performance so will be changing over to 98 (whenever I can get it) for a few months to see what its like.
From reading the forums and doing a bit of other study etc recently it looks like there might be a small economy improvement which should cover the small cost increase so I can't yet see any downsides.