Everytime I here someone mention greys, everyone jumps up with "get siemens 55 injectors or whatever ones they are and everyone then goes on to say, you cannot get them anymore.. which kind of leaves this debate dead in the ground. My Escort runs greys and has been live mapped. I get around 250 miles to a tank of super unleaded with some hard driving and some pootling around. A good amount of my miles is done on a cold engine. I am happy enough with that, it also goes like stink and greys can be had with relative ease. Everyone said bore wash etc would be an issue but a recent ctlinder test on my car has found the engine to be in great shape... I think the greys get hyped up with bad press like some other bits.