Earlier this year, Dodge wowed car lovers with the 2015 Dodge Challenger SRT Hellcat, which delivered a completely ludicrous 707 horsepower and could hit 199 mph. This engineering coup was well received, so it's no surprise Dodge then decided to stuff the same 6.2-liter HEMI V8 engine into the two-door Challenger's bigger brother, the Charger sedan.

What did catch our attention is the fact that even though the four-door Charger is 136 pounds heavier, it's the faster of the two cars. On street tires, it can run the quarter mile in 11 seconds, compared to 11.2 for the Challenger. Its top speed is a whopping 204 mph, enough for Dodge to call it the "quickest, fastest, most powerful sedan in the world." (Other high-end sedans can likely best the Hellcat, but their manufacturers electronically limit their top speed. And there are specially customized rigs like the Brabus Mercedes E63 that can go faster. Still, 204 mph is really, mind-blowingly fast.)

So how can the four-door Charger outrun the lighter Challenger, if they share an engine? It's all about aerodynamics. The Challenger has the look of an iconic muscle car, but that style doesn't do well in the wind tunnel. It "has this big front end which is more vertical," says Mark Trostle, head of design for Dodge's SRT division. "The mass that breaks through the air is larger." More wind resistance, less speed.

The Charger is heavier than the two-door Challenger, but it's also quicker thanks to "less of a brick" aerodynamics. Chrysler

The Charger, on the other hand, is "less of a brick." It's more swept back at the front, Trostle says, "a little more soft." The Charger's drag coefficient is .335, making the sedan much, much more slippery than the Challenger's .380. That's not particularly impressive compared to the Tesla Model S's 0.24 or the Toyota Prius' 0.25, but the huge improvement helps buy that extra 5 mph at top speed.

Looking at the front of the two cars, the Charger is (a little) more subtle, with a smaller, understated front splitter. The Challenger is much more aggressive and muscular, an intentional choice by the design team. The look of the Charger is "a little more sophisticated," Trostle says.

Let's note that the difference between 199 mph and 204 mph is more about bragging rights than actual usefulness (and that getting caught driving anywhere near those speeds on the street will get you a free trip to jail in most states). But bragging rights matter, especially when it comes to muscle cars. The fact that you'll be able to fit actual adults into the backseat of the Charger is an extra bonus. We imagine there will be more than a few folks heading to Dodge dealerships next year with just one question to answer: two doors or four?