Does anyone know what the brass spacers are for in the QA1 rear kit? I've positioned my cross member, my housing mounts, however I have not tacked my upper mounts yet. It's set up to be installed but I haven't yet because I'm not sure whether or not they need to be used on the upper mount which would change the width of the mounting tabs. It is the weekend so I can't call QA1, any quick info. would be great.