Paul, I know that I'm super jealous. The FD RX7 is one of my all time favorite cars, and in my opinion one of the most beautiful Japanese cars ever made.
I had an RX8 and absorbed some FD information, what I know:
Heat kills the rotary. They run hot and had cooling systems that were borderline inadequate. Upgrading the radiator and overflow tank is important, and consider a lower temp thermostat and cooling fan switch as well. The heat also tends to bake the hoses, so take a really close look at the vacuum and radiator hoses. If they're shot, get some silicone replacements in non-bling black.
They run rich, which kills the catalytic converter in the downpipe. If you can't go catless for emissions, if original you might consider replacing it. The cat will slowly plug, causing more heat, and the cycle continues.....
Racing Beat is awesome for parts and accessories, they actually did the engineering and parts for some of the factory Mazdaspeed cars. I'm sure there's other good suppliers as well.
Change the oil frequently, and check it with every fill up because they are designed to burn oil. I seem to remember that dino oil is recommended for them but I'm not 100% certain.
That's about all I can recall. Upgrade the cooling system, keep it in good tune, and you'll have a really fun reliable sports car.