I have used 95, 97 and Vpower Racing on my Golf GTI and I can confirm that there is definitely a difference between them. If the older TFSI engine in GTI created in 2004 can extract extra HP from premium grade fuel, I am very sure the newer N20 can extract the same if not more from the same premium petrol. Besides higher octane that prevents premature combustion before achieving the optimum compression in high performance turbo engines, premium grade petrol also contain better grade additives that reduce friction and cleanse your engine. In addition, premium grade gasoline is more combustible compare to lower grade fuel and this gives you a better response. All these adds up to give you a better driving performance. You pay for what you get.