Give that bitch a tune up first.... Even when you are modding your car... there are a few things that you should watch out for....
RX-7s are notorious for overheating... and for having a flooded engine.
I'd recommend what I did... Go to Advance Auto Parts... and buy a Haynes Manual for the 86-91 N/A RX-7. Then... go to your car... and read and follow the what the manual says... Start as little as learning as to brake master cylinder to the location of the gas tank... etc.. etc...
The Haynes Manual is a worthy investment...
Oh... and to be very honest with you.... You will fuck shit up... I did.
.... Shit happens.
Have fun...
Then after that I say that you should slowly start looking into mods...My FC is my daily driver... and I'm still getting used to it. Learn before messing with anything.