Some company really needs to package this in a 52mm or 60 gauge format. All (well both of them) knock sensors are very crudely mounted and finished off in cheap plastic housings. I dare you to find a place to mount either where they are clearly visable and look like they belong. I would pay dearly for something that was complete, and came in a gauge housing that could be mounted just about anywhere.
Kind of like what AEM did with their UEGO A/F meter. Before them, no one even made something that was packaged so well.