Improve your Miata's efficiency! Mazda did a decent job of smoothing the underside of the ND, but there are still some gaps. These flat panels are shown to decrease drag by 10 points, leading to a higher top speed and better fuel economy. Okay, it's not a massive change but every bit helps. These should also help drive your diffuser.

Made of powdercoated 5052 aluminum. Simple installation. Sorry, it only fits cars with manual transmissions.