The windshield wipers work sporadically, sometimes not at all.
The moon-roof will not close all the way.
Driver side seat belt does not retract quickly.
Even though I have only had this car for a few days, it feels extremely strong. The engine revs freely and easily, and the transmission engages quickly and easily as well.
When you drive the RX7, you never feel as if you are out of control. It never tells you anything that isn't happening, and it never asks too much of you - except maybe a heavy right foot.
The low seating position takes some getting used to, and late afternoon glare can be annoying, but that can be fixed with aftermarket tint.
I just wanted to comment on the issue with the seat belt. I had the exact same problem and then it failed to move at all. The good news was there was a recall on some Rx7's. You might want to check your VIN with the local Mazda dealer and see if it is covered under the recall.