Higher octane doesn't mean more power (if anything, the greater percentage of additives may actually reduce the calorific value of the fuel).
It means it can be burnt in a highly tuned engine with a greater margin over detonation occurring which is where the fuel burns in an uncontrolled manner causing a great deal of mechanical stress and excess heat, and, if it goes unchecked for more than a few seconds, causing serious damage.
Knock sensors are there in modern engines to detect this and respond by retarding the ignition and, on turbocharged engines, sometimes reducing the boost pressure. This reduces the performance of the engine.
The upshot is that it makes a great deal of difference to those who run highly tuned or turbocharged engines. The engines used in the Omega aren't turbocharged nor particularly highly tuned so they are unlikely to go into knock retard on 95 octane fuel, meaning there is unlikely to be much to be gained from Super Unleaded.
Kevin