So..... the car developed a slight miss under high boost. I have done all your regular checks, plugs, leads, coil packs, fuel pump, all wiring etc etc. I couldnt seem to get to the bottom of it so decided to bring it to a local silvia specialist. He is going through it to try an get to the bottom of it. One thing he wasnt happy with was having the AFM on the opposite side to normal? I am not up to speed mechanically to give an opinion but what do people think? Is he correct in wanting to move it to other side?