As an aid to race shops and independent builders, Spec MX-5 Challenge has released a version of a build sheet for the 2020 Spec MX-5 race car. The build sheet shows required and optional parts, current pricing (while Mazda is offering 20% off of required parts through January 31, 2020), sources and estimated labor hours.
Here is an example of how the sheet is laid out:
Of course, each build will require slightly different components based on the condition of the donor car. In addition, driver budget will have an impact. Finally, optional parts, like seats or data systems can range greatly in price.