I have heard arguments before that we have "better" synthetic oils here, and might be true, but it does sound a little odd that there would be a difference now days when everything is being shipped all over the world and back. The quality of Nitro is an interesting idea, the price is much higher here (I would have to pay about $40 for one litre of nitro) and that might mean that we are used to a higher quality too. I will have to dig up some litmus paper...