I've just starting using Gull Force 10 here, it's 98 octane with 10% ethanol. Until now I've been using BP 98, but having moved to an area where Gull operates I've discovered the rorts that BP in particular use. Like competing on the price of 91, but jacking up 95 and 98 prices to subsidise it. Anyway, this seems to have added 10% more feralness. The response when overtaking is noticeably better, the butt dyno feels like another 10KW. My wife commented on the different engine sound now as well. This shouldn't be the case because 98 is 98, but I'm wondering if BP sometimes isn't. Perhaps it's losing the effectiveness of its octane additives while in storage or transport. Anyone else running ethanol blends?