I don't have a Spec Miata, but have the same OEM gas tank as Spec Miata.
It's a '95 1.8 and was having fuel starvation issues on hard left hand corners this weekend at Heartland Park. Had maintenance throttle, but when pressing the 'Go' button past the apex, had NO power until the car straightened out. Dangerous for people behind me expecting me to take off. So pulled off the racing line and came back to the pits.
After troubleshooting all the relays a few weeks back I did replace the fuel pump after having no starting issue. Car idles fine, and runs great in a straight line. I went to a local O'Reiley's Auto Parts on Saturday and replaced the fuel filter. No change. I added almost a half tank of gas Sunday morning and problem was better, but still existent.