Miata Door Bushings
Simple mod, with function and form.
In a convertible, the door can become a crucial part of the chassis' structural integrity. Your doors are held closed by the latch, but they brace the chassis with a bracket on the door that grabs a soft rubber bushing on the body. This connection makes it easy to align during mass production, but it’s not nearly as secure as it could or should be.
These bushings will lock the door solidly into place by replacing the soft rubber bushing with a stiff and adjustable Polyurethane version. Not only does this stiffen the car for performance benefits, but the stiffer chassis will also reduce squeaks, rattles, and cowl shake/shudder.