Maybe wait for the next tankful?
When I crossed from 95 to 97, I did notice that my engine was slightly quieter when starting and idling, but DID NOT notice any improvement in power. Fuel consumption actually deteriorated!
However, on my 2nd and 3rd tankfuls of 97, mileage has actually gone back to normal. My butt dyno still can't detect any perceived extra boost, but I do definitely enjoy a smoother drive.
The problem is, I'm not sure if these perceived benefits are worth the additional cost! :stupid: