Also changed the cabin air filter (air conditioning and heater intake)--that one definitely was still factory. Even though I am not sure the generic Purolator filters I got at Advance Auto Parts are the absolute best replacement for the OEM parts, I am certain it's better then the filthy ones they replace.
I used the remaining few minutes of daylight after work to do the swap, right in the company parking garage. Took me all of 10 minutes per filter. Didn't need any tools either.
Brakes from Carbotech arrived today, but could not be delivered, because they weren't addressed right. I called UPS and corrected the address and they should have no problem to deliver them now.
Once the brakes are on, only three things will remain, but those are pretty big-ticket items: All fluids, street tires, and finally competition tires. I do hope that Miata sells soon!