The MAZDA MIATA M edition seats are the ones without the integral head rests. The head rest is on posts that slides into the seats - so easily removed. Inexpensive recover kits are readily available for them too. The high back are safer in preventing neck injuries but to me that isn't a concern in a plastic car. Here's example of a 1995 M edition seat. Covers are from Leatherseat.com or Katzkin - they seem to be about $600.