15. Mazda RX8
The RX8 was an interesting car when Mazda presented it. And not only for its Wankel engine, but for its unusual four-door/four-seat configuration. However, despite delivering up to 280 HP from its rotary engine, it wasn’t as fast as Mazda hoped it would be.
The reasons were that the engine didn’t provide enough torque for convincing acceleration times. Also, the car wasn’t light as it could be. Along with the typical Wankel rotary motor problems, this car is the perfect candidate for a V8 swap.