'Stratification' is the build up of 'layers' of something isn't it? What layers?
The only way to really know if the car runs better on super or regular is to stick it on a dyno in controlled conditions.
If it says on the petrol cap (or handbook) to run the car on regular (95) then that is what the car is mapped to run on. Running anything higher will not produce more power from the engine and can potentially hinder performance.
The only thing you may see a very slight increase in is fuel efficiency and the cleaning additives that are included in a lot of the super fuels allowing the engine to maybe last longer. The extra cost doesn't really make it worth it though in the long run.. especially when you can buy a bottle of reddex once every couple of weeks from Halfords for 99p instead.
To those that say 'you can feel the diference' (I would say have most likely experienced the placebo affect of filling up with 'SUPER FUEL!'), I say prove it..