showing that you didnt know it was bp stuff doesnt that show that petrol is abit of a placebo in a way. most people fill up at their perferred stations. When they change I think they are being extra pineckty and listening out for noises. If you look on the internet you will see posts like "filled up with tesco 99, made my car run crap so im back on v power." i doubt the engine could tell too much bar the detergents. I dont think it would map its self different either. im not saying this againt regular vs super but just reg vs reg or super vs super.