10 Classic Sleeper Cars You’ll Never See Coming

If the old 'never judge a book by its cover' adage was an automobile, then a sleeper car perfectly embodies the metaphor. Over the years, the sleeper car has become a well-respected hot-rodding tradition perfected on the streets and home garages. Unfortunately, only real gearheads recognized the understated joy of flying under the radar in a classic sleeper car while having the time of their life.

Fast-forward to the present age of exotic supercars, uber-expensive sports cars, and high-end opulent SUVs, it's unsurprising that these classic sleepers are quickly frowned upon in traffic. Nonetheless, the uninitiated are always taken aback by the beastly capabilities of these performance tricksters disguised in unassuming exteriors. And since the sleeper car culture is still alive, here's a list of classic sleepers you'll never see coming.

10 Ford Taurus SHO

Ford Taurus SHO (First Generation) — Via Mecum Auctions

To some, the second-generation Taurus SHO is another affordable mass-produced sedan from an automobile era riddled with annoying quality issues. However, this unassuming performance variant is one of the most iconic American sleepers, equipped with 15-inch wheels, heavily-bolstered sports seats, dual exhausts, and a reworked suspension compared to the standard model.

Ford Taurus SHO Rear View — Via Mecum Auctions

The main highlight of the Taurus SHO was the potent 3.0-liter Yamaha-tuned 24-valve V-6, capable of delivering a whopping 220hp and 215lb-ft of torque. With a top speed of 143 mph and a 0-60 mph time of 6.7 seconds, the high-performance Taurus SHO turned the four-door sedan class on its head and outperformed most premium-priced offerings of the time.

9 Saab 9-5 Aero

Saab has earned a reputation for making oddball cars with interesting individuality, making them the perfect impersonation of wolves in sheep's clothing. The first-generation Saab 9-5 Aero received a significant update in 2006, introducing more aggressive exterior styling, a distinct grille, new instrumentation, and rigid shock absorbers.

The Saab 9-5 Aero business side employs a potent 2.3-liter inline-four capable of a jaw-dropping 247hp and 273lb-ft of torque. However, variants with a Hirsch performance package elevate the performance to insane levels, upping the output to an insane 306hp and 302lb-ft of torque.

8 Chevrolet Impala SS (7th Gen)

With the rise of the SUVs in the '90s, fans of the Impala series were both thrilled and surprised when Chevrolet revived the sedan after a decade-long hiatus. The seventh generation Impala SS boasts a rounder exterior styling, cruise control, analog gauge clusters, remote-controlled power lock doors, power windows/mirrors, eye-catching interior design, and high-quality leather upholstery compared to its predecessor.

The most notable change from the previous generation was under the hood, with Chevrolet equipping the Impala SS with a 260hp 5.7-liter Corvette-derived LT1 small-block V-8. This potent engine makes the Impala SS faster than the BMW 5-Series of the time, claiming 0-60 mph in under 7 seconds and a top speed rated at 142 mph.

7 BMW E28 M5

The first BMW M5 holds significant provenance in the BMW M history, a segment founder that set the benchmark for the high-performance sedans that have since rolled off Bavarian production lines. From the old-school kidney grille to the classic split notchback and spoiler lip, the E28 M5 is a fully-fledged classic limousine with an understated design impression.

The E28 M5 performance magic comes from the 3.5-liter inline-six cylinder M88/3 engine under the hood, delivering an impressive power output of 278hp at 6500rpm and 251lb-ft of torque at 4500rpm. The 6.5-second 0-60 mph time and 152 mph top speed made the E28 M5 one of the fastest street-legal sedans of the time and certainly a worthy sleeper for cruising on today's highways.

6 Mercury Marauder

Mercury Marauder in black, parked — via Bring a Trailer

Admittedly, cars like the Mercury Marauder are a dying breed, but the fact that the name still lives on after the brand ceased to exist is a statement of its badass demeanor. The second-generation RWD Marauder is an underrated yet well-rounded muscle sedan with a monochromatic trim, sophisticated interior, 18-inch wheels, and performance-tuned suspension.

If you overlook the arguably mature and practical exterior design, the high-performance Marauder is no slouch, housing a modular 4.6-liter DOHC V-8 capable of 302hp and 318lb-ft of torque. And despite the limited 117 mph top speed and 7-second 0-60 mph time, the Marauder has gained so much appeal over the years to warrant a loyal cult following.

5 Audi RS2 Avant

The high-performance RS2 Avant emerged from the Audi-Porsche collaboration, an iconic piece of the forbidden German fruit that never made it stateside during the mid-90s. Interestingly, the joint project saw the original RS wagon inherit several Porsche 911 parts, including lights, mirrors, and Brembo brakes.

With Porsche AG making modifications like a large turbo, intercooler, radiator, fuel injectors, catalytic converters, camshafts, exhaust system, and ECU to Audi's 2.2-liter turbocharged five-cylinder engine, the AWD RS2 Avant turns into a cool sleeper wagon worth every penny. The 315hp engine allowed the RS2 to become the world's fastest wagon with a 163 mph top speed, making it the first Audi to smash the 155 mph barrier.

4 Mercedes-Benz E 60 AMG

Mercedes-Benz 500 E AMG — via Collecting Cars

The Mercedes-Benz 500 E is undoubtedly one of the most sought-after young classic models from the '90s, a modestly-designed model created in close cooperation with Porsche. As if that wasn't impressive enough, Mercedes-Benz upped the ante with the E 60 AMG, a rare model equipped with the Limited two-tone sports interior package, AMG suspension, AMG twin exhaust, and 17-inch EVO II alloy wheels.

Although the 500 E and E 60 AMG share similar exterior aesthetics, part of the upgrade included the larger displacement 6.0-liter V-8 engine that earned it the 'Hammer' nickname. The E 60 AMG makes a remarkable 375hp, enough to achieve a 173 mph top speed and clear 0-60 mph in 5.3 seconds.

3 Lotus Carlton

Black 1992 Lotus Carlton Parked On Road — via Pinterest

Nothing about the Lotus Carlton executive sedan screams excitement, from the uninspiring name to the lackluster design Vauxhall typically aimed at business people. Vauxhall and Opel wanted to improve the image of the most distinct offering in the lineup, so Lotus reworked the aerodynamics, suspension, and brakes, to create a supercar sedan.

The trick up the Carlton's sleeve is a modified 3.6-liter inline-six engine capable of a jaw-dropping 372hp, which makes it more powerful than the 316hp Ferrari 348 of the time. Despite hauling four passengers, the Lotus Carlton achieves an official 174 mph top speed, with 0-60 mph arriving in 5.2 seconds.

2 Bentley Turbo R

Bentley earned its stripes for delivering some of the finest craftsmanship ever seen on a luxury automobile, so, unsurprisingly, the Bentley Turbo R oozed style and luxury upon its debut. Unfortunately, its simplicity and boxy silhouette don't make it much of a looker by today's high-end luxury standards.

The current budget price ensures the Turbo R is no longer a symbol of status and wealth, but the 380hp 6.75-liter turbocharged and intercooled 16-valve V-8 makes it a classic sleeper with performance prowess. The Turbo R's ability to achieve a limited 150 mph top speed and clear 0-60 mph in 6.4 seconds could embarrass some modern vehicles on the highway.

1 Buick Regal GNX

The Grand National is arguably one of the most iconic sleeper cars ever to stalk the American streets, not forgetting that it's muscle car royalty and a crown Jewel in Buick history. The Regal GNX was the last hurrah for the standard GN model, characterized by meaner looks, all-black signature paint, air-to-air intercooler, Garrett T3 turbo, and stiffer suspension.

The improved engine controls, low-restriction exhaust, and free-flowing heads added to the 3.8-liter turbo SFI V-6 boost output to a massive 276hp and 360lb-ft of torque. Considering the inimitable 'Darth Vader' GNX stepped up to the greatest supercars of the time with a 124 mph top speed and 4.6-second 0-60 mph time, it's still a capable performance sedan by today's standards.