Can we chat about wing selection?
71" is the widest on offer for the Miata. What we found going 71" isn't the worst thing. Unlike other cars, the Miata likes to make front downforce. On our CFD testing of the medium df kits, it makes a health front bias. With our 64" wiags near 5*AOA, we reached a good balance. Which means a wider wing or a 1/2" gurney flap can run less aoa and get slightly less drag.
Link to downforce kits https://9livesracing.com/pages/search-results-page?collection=all&page=1&rb_snize_facet1=Aero+Packages