I hate having to say this every couple weeks or so but:
Very sorry about your car and I hope you find it or resolve the situation otherwise to your satisfaction.
Rx-7s are very easy to spot, open and take. They are not only rare and popular, but also known and liked by the criminal element. I was fortunate enough to watch my stepdad get about 4 Rx-7s stolen in a year while we lived on Miami Beach. I have also had to "steal" my own car many times so I know how easy it is. There are things you can do to deter theft, like the stuff mentioned in this thread, but never forget:
A towtruck CAN and WILL hook up to your car and take it in seconds, NO MATTER WHAT YOU DO. The car can also be dragged down the street with a regular truck, so they have more time and privacy to do whatever else is necessary. Therfor:
(This is going to sound harsh as fuck) IF YOU DO NOT HAVE AT LEAST A TINY SINGLE GARAGE, owning Mustang, Grand National or Rx-7 type cars comes with a HUGE risk of theft. Sure, garages can also be easily broken into in seconds but:
1. No one will spot the car by simply driving around in the neighborhood.
2. There are a million additional things you can do to protect the car inside.
3. When your tiny dog alerts you that someone is fucking around in the garage and you turn them into pizza with the Mossberg pump, you don't need to drag what used to be a human into the house.
Here is an example of what can be done inside a tiny single garage, in addition to the alarms, cameras, dogs and guns:
(PLEASE WATCH THE END OF THE VIDEO ONLY - start at 3:45)
Very sorry again and good luck. Sometimes I seriously get a perverse thought that at least if God forbid they ever break into my house again, there will SURELY be one less of them fuckers (I don't want to kill but I simply cannot risk retaliation against my family after blasting off each limb, or a dumb ass lawsuit by the robber, which has happened before).