well, the advantage of the wankel engine is that is very small, light and produces a lot of power; and can produce high revs because it isnt doing an up and down motion like the regular piston engine. The other positive is that because a rotary or wankel engine, rotates, it reduces a lot of vibration. regular piston engines have counerweights to couner balance the force of the expanding gases after the combustion stage. The rotary engine was first used in a small lawn mower back in the early days. then Mazda re designed it and fixed a few problems it had and patented it and has used it since the Cosmo in a large number of its sport and some saloons, and yes, Mazda is the only automobile manufacturer that has used the rotary engine. The wankel engine is also more efficient in the snese that i doen't lose much energy transfer to the the flywheel, and driveshaft and to the rear wheels, because all of it is in a circular motion, just like the engine. I personally love the rotary! I think it is very different, sounds awesome and it's engineering and physics is quite fantastic! The idea of the wankel rotary was performance and power with a small and lightweight engine, without efficiency on it, it is true that you lose a little bit of gas when the apex seals go over the spark plugs, and that some exhaust gasses can get back into the combustion chamber when the selas go past the plugs, but if you think about it, the change is very minimal, as the rotor is going at high speeds. Again like i said earlier, the wankel was make with performance in mind, i still think it is a fantastic engine!