Never judge a book by its cover. The proverb suggests that the content is more powerful than the exterior. The same applies to cars. Many drivers wish to drive fast cars but can't afford sports cars such as the AMG GT or the 911 Carrera. Numerous automakers have manufactured fast vehicles but have not received credit for the car's powerful engine due to the exterior that suggests the car provides mediocre speed. Some cars have a flashy exterior but don't have an engine that provides performance. Those cars have a bigger bark than a bite.

Updated February 2022: If you're looking to buy a sleeper that's capable of leaving much more exotic machines in its dust, you'll be happy to know that we've updated this article to include even more fast and inconspicuous vehicles for you to consider.

We intended to find cars that had a bigger bite than its bark. The only way for us to find out which cars provided good performance was by being objective about the car's exterior and focusing on the car's 0 to 60 mph and top speed. Our inquiry led us to discover cars that aren't expensive like the latest Porsche, yet provide the same performance. The search we conducted affirmed that the engine determines the speed of the car regardless of what the exterior looks like. We discovered cars that look like sleepers but have a roaring engine that provides great performance when the driver puts a foot on the pedal.

20 Cadillac CTS-V

2004 CTS-V
Via: Cadillac

The Cadillac CTS-V looks pretty much identical to the regular CTS. However, pop the hood, and you'll find the same engine as in the Corvette - a massive V8 that produces a whopping 640 horses. This beastly engine is coupled to an eight-speed automatic transmission that sends all the power to the rear wheels via an electronic limited-slip differential.

This formula makes for the perfect sleeper sedan that's capable of keeping up with supercars without even breaking a sweat. The CTS-V is a four-door sedan muscle car, but it's also very refined and offers a relaxed and pleasant driving experience for those times when you aren't beating sports cars into submission every time the lights turn green.

19 Dodge Magnum SRT8

Via Pinterest

The Dodge Magnum might look like your everyday station wagon, which means it's fairly inconspicuous - making it the perfect sleeper. However, while it's perfectly happy hauling around the kids and groceries, it's when the pedal is mashed to the floor it really shines.

Not much separates the SRT8 from its basic sibling - the only differences were bigger wheels, a hood scoop, and a few SRT badges. However, under the innocent exterior it was a whole different beast that packed a Hemi V-8 engine that transformed it into a sleeper wagon.

Related: 10 First Steps For A DIY Sleeper (And 10 Mods That Are Always Mistakes)

18 Chevrolet SS

via Reachmesocial

One of the automakers that most people didn't expect to produce a fast car was Chevrolet. The U.S. automaker has produced magnificent vehicles such as the Silverado and the Suburban, but most people who drove the SS were surprised to see that it produced a good performance.

When Car and Driver tested the 2014 Chevrolet SS, they discovered that a V8 engine lay under the bonnet and could produce 415 horsepower, allowing the car to reach 0 to 60 mph in 4.5 seconds. The car reached a top speed of 160 mph and had a base price of $45,000.

17 Mercury Marauder

via Hemmings Motor News

Mercury started the production of the Marauder in 1963 and ended it in 1970 before reviving the brand in 2002. The car derived its name from the most powerful engine available to the Mercury line. The automaker marketed the car as a high-performance version of the full-size product range.

Consumers who purchased the 2003 model would've discovered that the 4.6-liter V8 engine was capable of producing 302 horsepower. The car needed 5.1 seconds to reach 0 to 60 mph and had a top speed of 189 mph. The Marauder cost just over $30,000 when it debuted in 2003.

16 Ford Taurus SHO

2019 Ford Taurus SHO
via Wikipedia

Mustang is one of the few Ford models that has garnered a reputation for delivering speed. Most consumers who laid the eyes on the Taurus SHO (Super High Output) wouldn't have believed that the car had a 3.5-liter Ecoboost V6 twin-turbocharged engine that was capable of pumping out 365 horsepower.

Esquire magazine named the 2010 Taurus SHO Car of the Year. Ford introduced the car in 1989 and kept it in production for ten years. The automaker sold more than 106,000 units during that production run. The Taurus SHO returned in 2010.

Related: The 20 Best Sleeper Cars Money Can Buy (And 5 That Are Slower Than They Look)

15 Mercedes R63 AMG Minivan

Mercedes R63 AMG
via Loeber Motors

The German manufacturer's A and B series aren't known for producing blistering speeds, but the R-series is an animal when unleashed. Although the R63 is a minivan that looks like it suits a soccer mom, the car boasts a 6.2-liter V8 engine that can produce 503 horsepower, according to The Drive.

Drivers who want to reach 0 to 60 mph in 4.6 seconds should opt for the 2007 model. The R63 AMG is capable of reaching a top speed of 155 mph. Consumers who want to own the 2007 model should be prepared to pay around $29,000.

14 Lotus Carlton

via Car Throttle

Many drivers in North America won't be familiar with the Lotus Carlton since the car wasn't federalized for sale in the U.S. Otherwise known as the Vauxhall or Opel Lotus Omega, the Lotus Carlton was an upgraded car that Lotus propelled to high speeds. The car was in production for only three years but could reach a top speed of 177 mph. The Carlton boasted a 3.6-liter twin-turbocharged engine that could produce 375 horsepower.

The car needed just over 5 seconds to reach 0 to 60 mph. Although the car was in production from 1990 until 1992, consumers shouldn't be surprised to pay over $60,000 for the car.

13 Volvo S80

via Car & Driver

The Swedish manufacturer is known for producing safe vehicles. Most people don't know that the S80 is not only safe, but it's fast, too. The car went into production in 1998 and lasted until 2016. Consumers who bought the 2007 model had an option between two engines.

According to Car and Driver, consumers who opted for the 4.4-liter V8 engine, made in Japan by Yamaha, would have experienced 311 horsepower. The car reached a top speed of 166 mph. Considering the Swedish manufacturer is known for making simple cars that provide a mediocre performance, the S80 is a superb vehicle.

12 Ford Flex EcoBoost

via Car and Driver

Flex is a mid-size crossover SUV that Ford manufactured since 2009. Many people have underestimated the car's capability and speed. Flex boasted a 3.5-liter EcoBoost V6 engine, capable of producing 365 horsepower.

The 2014 EcoBoost engine allowed the driver to reach 0 to 60 mph in 5.9 seconds. Apart from the high performance, Flex provided a comfortable interior with the latest gadgets. Consumers who were interested in getting the 2014 model with the EcoBoost engine would have paid just over $42,000.

Related: These Japanese Sleepers Are Insane With Some Under-The-Hood Mods

11 Mazdaspeed 6

Mazda Mazdaspeed 6
Best Car

The automaker from Japan unveiled the Mazdaspeed 6 in 2006. The car featured the most powerful piston that Mazda had produced. Don't let the 2.3-liter four-cylinder 16-valve engine make you believe that the car can't produce power.

The Mazdaspeed 6 can pump out 274 horsepower through the six-speed manual transmission. That much power allowed the Mazdaspeed to reach 0 to 60 mph in 5.4 seconds, according to Ranker. Who would've expected that from Mazda? The Mazdaspeed 6 is a perfect example of why one shouldn't judge a car by its exterior.

10 Audi SQ5

via Motor Trend

Audi introduced the SQ5 as a performance crossover. The point that the German automaker was trying to make with the SQ5 is that it could produce an SUV that provided safety, space and speed. Under the bonnet of the SQ5 was a 3-liter twin-turbocharged engine.

Drivers who put their foot on the pedal of a 2015 model would have experienced the 354 horsepower that allowed the car to propel from 0 to 60 mph in 5.2 seconds. That is a surprising amount of power for a crossover SUV. The car had a purchase price of $40,000.

9 Volkswagen Phaeton

via Car Gurus

Volkswagen kept the Phaeton in production from 2002 until 2016 but produced just over 84,000 units. Most people regarded the Phaeton as another sedan, but Volkswagen was adamant about changing that perception when it introduced the 2004 model with a 6-liter W12 engine.

Most people didn't expect the Phaeton engine to pump out 444 horsepower and reach 0 to 60 mph in 5.9 seconds. The car's top speed was 155 mph. Volkswagen priced the car at just below $90,000.

8 Ford Fusion Sport

via Motor 1

Ford enthusiasts often looked to the Mustang if they wanted a fast vehicle from the U.S. manufacturer. When Ford unveiled the Fusion Sport, most of the market was in awe that the car had a bi-turbocharged 2.7-liter V6 engine that could produce 325 horsepower. The engine yields 17 mpg in the city and 26 mpg on the highway. The car needs 5.3 seconds to reach 0 to 60 mph and costs $41,000 for a 2018 model.

Fusion Sport is not a typical family sedan. Drivers who opt for the Fusion Sport shouldn't push the limits of the car when transporting the family.

7 Lincoln MKZ 3.0

via Canadian Auto Review

Luxury isn't the only aspect that Lincoln owners can expect from the vehicles, as the U.S. automaker has ensured that the cars also produce plenty of power. Lincoln ensured that the 2017 MKZ could provide power, so the automaker fitted a 3-liter twin-turbo V6 engine that was capable of producing 400 horsepower.

When Motor Trend tested the car, the all-wheel-drive vehicle enabled them to reach 0 to 60 mph in 5.2 seconds through the 6-speed automatic transmission. Consumers who wanted the 2017 model would have had to fork out $59,000 when it debuted.

Related: 10 Sleeper Cars Only Gearheads Will Buy

6 Jeep Grand Cherokee Trackhawk

via Youtube

The reason most drivers opt for an SUV is the safety and better road visibility that the cars offer. Not many drivers expect an SUV to produce high performance. Considering that Jeep has produced the Cherokee since 1992, the automaker made several changes to the car to stay ahead in the SUV segment.

One of the changes was ensuring that the Trackhawk provided good performance. The car needs 3.3 seconds to reach 0 to 60 mph and has a top speed of 180 mph. The base price of the 2018 model is $87,000.

5 Toyota Avalon

via Wikipedia

The manufacturer from Japan has garnered a reputation of producing cars that are reliable, not fast. Many consumers demanded from Toyota to introduce a car that was reliable and provided good performance. The Avalon was a full-size car and Toyota's largest front-wheel-drive sedan. Under the bonnet of the Avalon is a 3.5-liter V6 engine, capable of spurting out 301 horsepower.

The car is capable of reaching 0 to 60 mph in just under six seconds. Considering the Avalon is a large Toyota, that is an incredible accomplishment. Avalon's base price is $43,000.

4 Pontiac G8 GT

via Wikimedia Commons

At first glance, one would say that the G8 GT looks like it can provide mediocre performance. Most people aren't aware that the G8 GT has boasted a 6-liter V8 engine that could pump out 361 horsepower, allowing the car to reach 0 to 60 mph in 5.2 seconds through the 6-speed automatic transmission.

The car's top speed was 161 mph. Consumers who wanted to get their hands on the Pontiac G8 GT would've had to spend around $30,000 for a 2009 model. That is not a bad price considering the power the car provides.

3 GMC Typhoon

via Hemmings Motor News

Whether you owned the Typhoon or the Syclone, you would've experienced blistering speeds from both cars. GMC produced the Typhoon from 1991 until 1993. During the three year production, the automaker produced just under 5,000 units.

Under the bonnet was a 4.3-liter V6 engine, capable of pumping out 280 horsepower. The car needed 5 seconds to reach 0 to 60 mph. The car was an all-wheel drive that received power through the four-speed automatic transmission. The only drawback of the vehicle is that it's not still in production.

2 Buick Grand National Experimental

via Barn Finds

Finding a 1987 Buick Grand National isn't the easiest task these days, but it will be worth your while once you grab the steering wheel and press the pedal. Under the bonnet of the Grand National was a turbocharged V6 engine that helped gain quicker acceleration, according to Top Speed.

Buick introduced the GNX (Grand National Experiment) for the final year of production. The car pumped out 276 horsepower and needed only 4.7 seconds to reach 0 to 60 mph. Buick charged just under $30,000 for the car when it debuted.

1 GMC Lingenfelter Suburban

via Kitchen Decor

The Lingenfelter Suburban is one of the most underestimated SUVs to emerge. When GMC asked engineer John Lingenfelder to produce an engine that would provide ample power, the automaker wasn't aware of how powerful the engine would be.

Consumers who bought the 1994 model would have experienced the 9.9-liter V8 engine. The car was capable of producing 550 horsepower and reaching 0 to 60 mph in 4.6 seconds, according to Ranker. The Lingenfelter Suburban produced 8 miles to the gallon. A 1994 model was available for $17,000 on classifieds.

Sources: topspeed.com, thedrive.com, roadandtrack.com, caranddriver.com, ranker.com, motortrend.com