When it comes to fast cars, designers will typically work hard to make it clearly obvious that it is indeed a performance vehicle. Clues like flashy aerodynamic elements, aggressive styling, and many bits of trim come together to make a car stand out and say "I'm fast," even if it isn't actually all that sporty.

A sleeper is the exact opposite of this, being a normal and rather boring-looking car that seems slow, but packing some serious performance under the hood. While the 1990s weren't the greatest time for performance, even in full-on sports cars, the game was beginning to improve, getting better and better as the '80s ended. Thanks to this, many '90s cars are still seriously cheap, and these 10 are some of the coolest sleepers of the time that you can buy for $10,000 or less.

10 Buick Roadmaster Wagon (1994-1996)

1996 buick roadmaster wagon
Via bloomberg.com

An old school wagon in general may not be the most exciting car, especially this family hauler, but are starting to gain some cool factor as a sort of ironic statement. Normally a slow barge on wheels, the final years of the Roadmaster included a shocking V8 secret.

Via Barrett-Jackson Auction

A plush, practical, and comfortable car, the Roadmaster was a relative sales success. Going on sale in 1991, the Roadmaster's 170 hp V8 certainly wasn't a fast car, but in 1994, that would change. Updated for 1994, the Roadmaster now came equipped with a genuinely exciting V8, namely the LT1 V8 taken straight from the Corvette. Now laying down 260 hp through the rear wheels, a 1994-1996 Buick Roadmaster wagon makes for one hell of a sleeper, especially with a wide selection of aftermarket parts to boost that power even higher. While more and more people are realizing its potential, driving up prices, the LT1 Roadmaster wagon can still be found for around $10,000.

9 Buick Riviera Supercharged

Via Cars Global

Another boring Buick from the '90s, the final generation of Riviera was a comfortable cruiser, but far from what you'd call a fun car. Despite that, much like the Roadmaster, the Riviera had a performance secret that is easy to overlook thanks to the outside image.

Via Cars Global

Released in 1995, the 8th generation Riviera was also the last, being killed off for good in 1999. Strangely curvy, with a blob-like design, the final Riviera was sold with a decently powerful 3800 series V6, making 205 hp in base form. A discreet upgrade, the Riviera was also offered with a supercharged trim, boosting power to 220 hp, and also offering a beefier transmission. For 1996, things got more powerful, and the supercharged Riviera now made 240 hp. A car few would expect to be supercharged from the factory, the Riviera Supercharged makes for a comfy low-key sleeper, and can be found for around $3,000.

8 Lexus IS300 (1st Generation)

Via: Lexus Corporation

Lexus' small and sporty luxury sedan, the IS 300 is still being sold today under a similar purpose. The original, though, is somewhat of a cult classic, with boring looks that bely a few virtues unknown to most.

Lexus IS300
Via Lexus

Released in 1999, the original IS 300 (called the Toyota Altezza in Japan) looks like a slightly sportier Corolla. What it lacked in stand-out looks though, the IS 300 made up for with performance. Fans of the Supra may be familiar with the 2JZ inline-6, and the original IS 300 came from the factory packing one, although in non-turbocharged form with 217 hp. Still quite fast when stock, the IS 300 has some awesome RWD handling, and can be tuned to produce some insane power (think 800 hp+) with the wide availability of 2JZ aftermarket parts, and as well can be found quite easily for around $5,000.

7 Chevrolet Impala SS (1994-1996)

Via Hagerty

Another seemingly boring mid-'90s GM vehicle turned from boring to awesome with the Corvette's V8 engine, the Impala SS was an awesome muscle car in a low-key package.

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With the Camaro and Corvette serving as Chevy's only real muscle offerings during the '90s, an idea came about to build a similar car to the full-size muscle cars of the '60s and '70s. Based on the 4th generation Caprice, the Impala SS came to life in 1992 for the SEMA Show. Put on sale in 1994, the Impala SS was RWD, used the Caprice's police package suspension, a set of thick sway bars, big disc brakes, as well as the LT1 V8 used in the Corvette. A thrilling car, and sick sleeper, the Impala SS can be found for around $10,000.

RELATED: The Real Story Behind The 1995 Chevy Impala SS

6 Volvo 850R

Via Bring a Trailer

Among the most iconic boring designs, Volvo's brick-shaped sedans and station wagons of the '90s were some of the last cars anyone would expect to be sports-car levels of fast, but, not all were slow, and versions like the 850R made for some sick Swedish sleepers.

Via Shmoo Automotive

Introduced in 1991, the Volvo 850 didn't look all that new compared to Volvo's previous boxy cars but indeed was a huge technological leap for the company with more refined and advanced construction. While not all that exciting performance-wise, Volvo changed that in 1994, bestowing the inline-5 with a turbocharger that brought it up to 222 hp as the 850 Turbo. Evolving into the Porsche-tuned T-5R, In 1996 the 850R followed it up with 240 hp, as well as sports car level handling. A flying brick, any performance-tuned 850 makes for a great sleeper, and the awesomely sporty, but rather rare 850R can be found for around $10,000.

5 Dodge Spirit RT

via zombdrive.com

Inside and out, the Dodge Spirit R/T looked like a terribly generic and forgettable commuter car. While that's an accurate assessment of the standard Spirit, the Spirit R/T was one of the most shockingly fast sleepers of the early '90s.

Via Pinterest

An economy-oriented K-car-based sedan filled with plastic on the inside, and designed without taking any real risks on the outside the standard Spirit was equally dismal when it came to performance. In 1991 though, Dodge released the Spirit R/T, completely flying in the face of everything that dreary Spirit had stood for. Powered by a turbocharged inline-4 developed with help from Lotus, known as the Turbo III, the Spirit R/T could throw down 224 hp through its front wheels. That may not seem all that impressive today, but back in 1991, that power was enough to let the car outrun far more prestigious competition like the BMW M5 and Nissan 300ZX Turbo. Incredibly rare to find, project-car condition Spirit RT's can occasionally be found for dirt cheap, and proper examples should be around $10,000.

RELATED: 5 Criminally Underrated Classic Dodges On The Used Market (5 To Avoid At All Costs)

4 Ford Thunderbird Supercoupe

ford thunderbird supercoupe 90s
Via Mecum Auctions

Starting off life in the '50s as Ford's personal luxury car with some proper muscle capabilities, the Ford Thunderbird was a spectacular car for the first few generations but slid further and further from its roots during the '70s.

Via Wikimedia

Starting in 1989, and sold until 1997, the 10th generation Thunderbird was released with the Supercoupe acting as the top trim, equipped with a surprisingly quick supercharged V6 making 210 hp. One of the last old-school style big and comfy RWD coupes, the Thunderbird Supercoupe is a lot faster than it seems and is overall an experience you just can't get anymore. Somewhat of a cult classic, the Thunderbird Supercoupe can be found for under $5,000 with a bit of hunting.

3 Jeep Grand Cherokee 5.9 Limited

Via DrivingLine

The '90s equivalent of the Jeep Trackhawk, the Grand Cherokee 5.9 Limited isn't the fastest sleeper out there, but when compared with just about every competing SUV from the '90s stands out as a true performance powerhouse.

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While mostly forgotten today, this boxy and unassuming Jeep was a true pioneer of the performance SUV segment that's ridiculously popular today. Starting with the solid but slow ZJ generation Grand Cherokee, the 5.9 Limited involved dropping in a 5.9 L Magnum V8, letting it make a powerful (for the time) 245 hp and plenty of torque sent through a 4WD system, as well as being outfitted with some top of the line luxury interior trim - this being a relative term when it comes to '90s Chrysler products. Only produced in 1998, the Grand Cherokee 5.9 Limited can be found for under $10,000 when one comes up for sale.

RELATED: Hennessey Performance Shows-off Their 1000 HP Trackhawk

2 Mitsubishi Galant VR-4

Via: Motor Biscuit
Via: Motor Biscuit

Having an image purely as a boring commuter in North America, the Galant sadly for us had its truly exciting versions kept from Americans, relegated mostly to the Japanese market. Among them was the VR-4, a rally-bred beast with some unsuspecting looks.

White Galant VR4 on road in colder weather
via RightDrive

Iconic among enthusiasts for their rally success, road-going beasts like the Lancer Evolution are among Mitsubishi's coolest cars. The Galant though did compete in the WRC before the Evo came about, and when homologated in 1988 as the road-going VR-4 was similarly monstrous with AWD and a wicked engine. That engine, in particular, was the 4G63T, which was the engine used to turn the Lancer into the Lancer Evo, and a tuning legend for its ability to handle some serious power. Sold until 1992 as the 6th Gen (pictured on top), the new Lancer Evo meant the next VR-4 wouldn't arrive until 1996 as the 8th Gen (pictured above). Either is a proper JDM sleeper, but the 8th gen is slightly easier to find and can be had for around $10,000.

1 Ford Taurus SHO (2nd Generation)

Ford Taurus SHO first generation
via pinterest.com

Judging by the looks, and associations of its name alone, the Taurus SHO should be an understandably forgettable, and downright boring car. But it wasn't, instead of being a shockingly fun thrill ride with surprisingly cool engineering under the hood.

Via Bring a Trailer

Originating in 1989, the 1st generation Taurus was about as boring as a sedan could be. Soft and filled with plastic, the Taurus was a strong seller but had no associations with performance or fun. Setting out to change that, the Taurus SHO was an intensive project and one that saw Yamaha collaborate with the blue oval, creating a seriously innovative high-revving V6 producing 220 hp - respectable sports car power for 1989. Carrying that engine over to the 2nd generation, which began in 1992, the Taurus SHO remained a subtle sleeper and surprisingly unique powerhouse. While rare, a 2nd gen Taurus SHO can be found for around $5,000 in decent shape.

NEXT: 10 Forgotten Facts About The Ford Taurus SHO