Your gonna need a strong diff, and big tires. I'm not sure how the RX-7 drivetrain will hold up, but I assume you have put that into consideration.

Reliability is the key to a fun track car, and good brakes.

As long as you have the tire to put it to the ground the torque will be fine. I wouldnt go crazy with the power mods until you get comfortable driving it at the track.

I would do the following in order:

Big brakes
Big tires
strong diff
suspension ( if you feel you need to change it)

Dont forget about safety items either, like roll cage, seats, harnesses.