I have stopped using optimax after getting a lecture about how it gums/fu*ks car sensors from countless people in the motorsport business. Plus i'm not keen on the way it makes the inside of the manifold, turbo, downpipe and exhaust ORANGE. Sainbury's super for me from now on. I don't notice any difference in perfomance and anyone that says they can notice 2-6bhp is telling porky's!! All the fuel in scotland is from BP grangemouth so 97 ron is 97 ron no matter which pump it's from. Saying that Optimax has got other crap in it that the other don't.