I have an Autometer Sport Comp that I mounted on a super strong magnet and just brought the wires up through the defroster vent. I put a 4-pin plug on it so I can remove it easily enough if I need to. The tach itself just mounts to the bracket that came with it. I don't have a good up close picture, but you can see it fairly well in the pictures attached. It works great because I can move it left, right, or center. I put a thin later of plastic-dip on the magnet so it doesn't scratch the dash if I move it. I don't move it often as the magnet is ridiculously strong and it's tough to get good leverage on it. I've picked up the front tire 10" or so on launch and it has never moved.
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