I'd like to hear opinions on fuel, the reason i ask is i am joining the darkside from a petrol car. The petrol was only ever ran on optimax (grey import WRX) and its been proven time and again optimax (now superseaded by v-max) gives high performance cars more power. I didn't think this would be the case with diesel but it looks like this fuel also varies in its performance. so do i stick with shell or go to BPor bung in supermarket grade diesel!? Is their conclusive evidence anywhere about the benifits of different diesel and what are they!? and also what is the differance between diesel and diesel extra, is it the same as un leaded and super ul ie higer octane rating?