We have a similar fuel here in Iceland which is called V-Power. However that fuel is not with an added octane booster but a high quality high octaine fuel. It is 99+ Ron and the Ferrari Formula 1 race cars can run on it without problems.
I have used this fuel for almost a year now without exception. I felt more power at first and it is easy to see wether it makes a difference by doing a little test.
Find a nice strip of straight and clear road.
Accelerate at 30 kmh in third gear and keep the speed constant. Mark two spots for measurement purposes, one to start accelerating at and one two take notice of your final speed in third gear.
You may not change gear so the strip must not be too long between the markers.
The point is this. You drive at a constant 30 kmh speed in third gear and when you cross the first marker you floor it! When you reach the second marker you must notice you speed or time your run.
You do this with a full tank of regular fuel and with a full tank of optimax and you should get a clear result of the any difference in the fuel quality.
If it works, you end speed should be higher. And there is no human factor in this either since you don't change gears and allow for a smooth run at 30 kmh for some time before you floor it.
Try this.
I did and the difference was about 4 car lengths over a 1/4 mile.
In favour of the V-Power
However I kept using this fuel mainly because of the cleaning qualities which are unsurpassed by any other fuel bar none!
). 
Linear Mode
