We offer two oil filters for your Miata. The standard size is a quality NPN unit, a direct replacement for what Miata specifies for the engine. We've used these for years and been very happy with them.
Our high capacity filter is 1" longer than stock for 40% more capacity. This means more surface area of the filtering media and less pressure loss through the filter. It also means it can trap more dirt before the bypass opens. This is a high quality Bosch filter with an internal check valve, just like the factory recommends. If you have the extra room in your engine bay - most Miatas do - we recommend it.