Cars can make and distribute power in many weird ways.
Today, the most common layout for a car's drivetrain is a front-mounted engine driving the front wheels. The advantage is that it's cheaper to manufacture a car that doesn't need to move power from one end of the car to the other, and the drive shafts don't need tunnels to run through that steal space from the inside of the car. However, front-engined rear-wheel drive cars give a balance between being fun for enthusiasts to drive by letting the front end of the car concentrate on steering while keeping the engine out of the way. Whereas a mid-engined car is ideal for balancing the weight of a performance cars chassis, but adds a whole lot of extra complexity while taking up space that could be used for passengers.
From those engine positions, there's a whole lot of variations that can be had depending on which wheels the power needs to reach, what the handling requirements are, and what design constraints are imposed in general. That's where things get really interesting and carmakers get creative, resulting in a range of differently designed drivetrains that challenge conventional thinking.
The GT-R is legendary for many reasons, and one of the unique tricks Godzilla has up its sleeve is in the powertrain. Usually, power in an all-wheel-drive system is distributed by a differential at the center of the car, but the GT-R's twin-turbo V6 is mounted conventionally up-front and sends its power all the way to the dual-clutch transaxle at the back, which sends power back to the front.
When Lamborghini produced the first mid-rear engined road car, it decided to go with a monstrous V12 in the Muira rather than a more compact V8. Rather than end up with an overly long car, and inspired by the Austin Mini of all things, Lamborghini mounted the V12 transversely, which means the engine is positioned width ways across the car rather than front to back.
What's better than a mid-engined V12 engine? A mid-engined V16 engine of course. Not only did the former Lamborghini engineers working for Cizeta-Moroder stick two V8 engines together, but they also mounted it transversely behind the driver.
Weird powertrains don't just come in supercars as evidenced by the original Volkswagen Beetle. The Beetle was weird and problematic in so many ways, yet somehow remained in production globally from 1938 to 2003, with 21,529,464 cars built. Drivetrain wise, the original Beetle had an air-cooled four-cylinder engine not just mounted in the back, but behind the rear axle driving the rear wheels.
Porsche mounts its engines in the rear for the 911, but over the years have moved them forward. However, the 918 was designed as a mid-engined plug-in hybrid sports car from the start. The drivetrain is fascinating, however, as in a move to lower the center of gravity Porsche mounted the PDK transmission upside down.
The F50's drivetrain isn't unusual in that it's a mid-rear engine car with the gearbox mounted behind the engine. However, like a race car, Ferrari saved weight by making the engine and gearbox part of the chassis construction. That means it takes part of the stress dealt out through the car as its driven. This isn't usually done on modern road cars because it brings a lot of extra noise and vibration.
Toyota's minivan was a weird fish. For some reason, Toyota started supercharging its 2.4-liter engines in 1994. If that's not weird enough, the engine in the first generation was fitted directly under the front seats to make the Previa a mid-engined and rear-wheel drive MPV. Now, while a supercharged and mid-engined minivan sounds like a lot of fun, changing something as simple as the spark plugs isn't easy when the engine is under the front seats.
Ford's RS200 was a European homologation car from the infamous Group B rally era. It was all-wheel drive and, like the GTR, had a weird way of distributing power. The RS200 had a rear-mid mounted engine but the transmission was in the front while the differential in the center distributed the torque to all four wheels.
Ferrari also decided a V12 was the way to go when Enzo Ferrari was finally convinced that the people that bought his road cars could handle a mid-engined car. In order to keep the center of gravity as low as possible, Ferrari used a flat V12 engine. Curiously though, they negated that advantage by mounting the engine above the gearbox rather than in front of it. Then, Ferrari did exactly the same thing with the later Testarossa model.
When starting a new design from scratch, putting the engine right at the back of a car is a strange choice. But, it was Ferdinand Porsche that designed the Beetle and that basic layout ended up being used for Porsche's early sports cars and the long-running 911. The benefit is having weight over the rear wheels to help grip, but that weight also helps the car act like a pendulum once that grip starts to go away.
The downside didn't affect the Beetle too much because it was underpowered, but the 911 is a sports car and designed to be driven fast. Porsche has refined the 911 over the years to truly take advantage of the weight distribution while making the handling characteristics less likely to bite an unwary driver.
A powertrain is often defined by its engine. Ideally, that engine needs to be as small and as light as possible, and Mazda approached that by spinning a three pointed rotor inside the engine housing to create three moving chambers used for the four phases of the power cycle. The end result was, literally, a revolutionary engine that was not just small and light, but makes high horsepower relative to the displacement of the engine and revs all the way up to 9,000 rpm. Unfortunately though, there are downsides to the rotary engine. Mainly that the rotor tips wear quickly if the engine isn't driven and maintained properly.
The Wankel Rotary engine gained popularity in Mazda's RX-7 and then was retired along with the RX-8 in 2012.