RX7 is easily the easiest car out of the bunch to maintain and make power on. I have owned many rotarys of all 3 gens. If you want a really fast car, buy an old Spec7 racecar that is still street legal, then drop a TII motor in it. If you know what you are doing, you can easily make about 250rwhp reliably in a car that weighs 2200lbs (w/full int). With minor mods, the car will easily outhandle most modern sports cars, and an old Spec7 car will already have the suspension.

The second best car would be the Miata. Bullet-proof, and Spec-Miatas are available as well. Drop a supercharger on a 1.6 and it will scream.