Tein has esablished themselves as one of the go to choices when looking for a Coilovers for the Miata. The Tein Flex Z is a great suspension upgrade that will grant you better handling giving you a more enjoyable driving experience. This setup is perfect for Dual Duty applications, it will be smooth and comfortable while daily driving and will hold its own when taken to the track or autocross.
I have these on my personal car and they are great! A good compromise between everyday ride comfort, I have the dampening set at the softest setting and track use.