If You're Looking For An Affordable Sleeper, These Cars Should Be On Your List

Flashy sports cars are not for everyone. Some dream of winning pink slip night races with a sleeper car — a vehicle that looks innocuous but hides an element of surprise. However, a sleeper car can cost a bomb to build if you are chasing 1,000 horsepower and looking to make a career out of racing for slips. For the more normal enthusiast, sleeper cars like these are an affordable way to attain motoring nirvana. 

We are talking about used sedans that offer outputs of 400 horsepower and more. They also provide comfort and luxury, all at a low price of less than $15,000 if you know where to look. That said, there are certain caveats associated with these cars. While they are relatively affordable now, they did command a sizable premium when new, and you'll have to spend luxury car maintenance money for many of these cars. So, make sure you look for a well-maintained, low-mileage model, even if it means you have to shell out a bit more for the car. With that nugget of wisdom out of the way, these are our picks for the best affordable sleeper sedans. Let's revel in the joys of depreciation.

Want an M5 without the sporty styling? The BMW 550i is the closest you can get to an actual M5 thanks to what's under the hood. The fifth-generation 5 Series (E60) got the 550i variant in 2006, which came with a 4.8-liter V8 delivering 360 horsepower and 360 pound-feet of torque. However, we are more interested in the sixth-generation 5 Series (F10) launched in 2011, which came with a new V8 engine. While the V8 was downsized and now displaced 4.4 liters, it featured twin turbochargers, which pushed output to 400 horsepower and 450 pound-feet of torque. The motor and all-wheel drive setup allowed the luxury sedan to sprint from 0 to 60 miles per hour in 5 seconds. The same formula was seen in the 2021 BMW M550i. 

Today, you'll find plenty of used E60 and F10-generation 5 Series 550i cars in online classifieds with prices as low as $6,000. The F10 generation is the one to go for, as they are better styled and have more power. Also, keep an eye out for the manual variants that keep coming up for sale.

Go to YouTube, and check out the muffler-free Volkswagen Phaeton W12. I promise you, once you hear it, you'll want one. Thankfully, used Phaetons have depreciated quite a bit since the luxury sedan was first introduced in 2002. The hand-built car had the same platform as the uber luxurious Bentley Continental GT and came with a choice of a 4.2-liter V8 or a 6.0-liter W12. The latter was developed for Bentley and made by fusing two Volkswagen VR6 engines, delivering 420 horsepower and 406 pound-feet of torque to all four wheels, an impressive number at the time. It was fast but not supercar-baiting fast, owing to its large, heavy bodyshell. It can travel from 0 to 60 mph in 5.5 seconds, and the top speed was limited to 155 miles per hour. Unrestricted, it can hit 178 miles per hour.

Unfortunately, Volkswagen lacked the brand value of its rivals like Audi, BMW, and Mercedes-Benz. Think of it, would you rather spend close to $100,000 for a Volkswagen Phaeton or a Mercedes-Benz S-Class? This turned out to be the Phaeton's undoing. Today, a used, high-mileage W12 Phaeton can be had for as low as $11,000. However they can be hard to find, as the Phaeton was only sold in North America between 2004 and 2006.

Forget the engine for a moment. What you have is a hand-built luxury car rivalling the likes of the Mercedes-Benz S-Class and BMW 7 Series. You probably won't be racing for slips in the Phaeton, but you may end up barreling down the highway in this high-speed express in utmost comfort. That's a different kind of high.

The Audi S6 allows you to own a screaming, thoroughbred Lamborghini V10-engined sports car. The S6 was the sporty middle ground between the A6 and the hardcore RS 6 and featured inline five-cylinder engines and V8s. That was until the third-generation S6 came out in 2006. With the A6 now featuring the previous-generation S6's 4.2-liter V8, Audi decided to use its sister company, Lamborghini (both Audi and Lamborghini are under the Volkswagen umbrella), and plonked the Gallardo's V10 motor into the S6. Unlike Lamborghini's 5.0-liter V10, the S6 featured an enlarged 5.2-liter V10 powerplant. It made less power than the Gallardo (429 vs 493 horsepower) but put out more torque (398 vs 376 pound-feet). The S6 also used a torque converter with its quattro AWD setup, unlike the Gallardo's single-clutch gearbox. Together, they made the S6 a brilliant sleeper car that could accelerate from 0 to 60 mph in 5.2 seconds and sound like a bat out of hell.

The V10 was only offered with the third-generation S6. The fourth-generation S6 (2012 to 2018) got a downsized twin-turbo 4.0-liter V8, which delivered 414 horsepower and 406 pound-feet of torque. When new, the third-generation S6 was priced around $75,000. With the time for reason ending, buying a depreciated V10 S6 is a compelling argument. Today, you can find a few used V10-engined S6s under $15,000. Early examples of the third-generation Audi S6 can be had for under $10,000, but you will have to look far and wide. Most examples on classifieds are high-mileage models, and getting them to mint condition can be a financial nightmare, so tread carefully.

Volvo introduced the S60 with plug-in hybrid powertrains in 2019. More importantly, the Swedish carmaker introduced the S60 T8 and T8 Polestar, both of which offered 400 or more horsepower. This was done via a clever setup consisting of a 2.0-liter inline four-cylinder engine that's both turbocharged and supercharged and coupled with two electric motors driving the rear wheels. So, you have an AWD sedan that delivers 400 horsepower and 472 pound-feet of torque (the T8 Polestar offers 415 horsepower and 494 pound-feet). That's a four-cylinder motor delivering more power than a V8!

In 2019, a new Volvo S60 T8 Twin Engine was priced at around $55,000 onwards. While a used Polestar will be almost impossible to get with our $15,000 budget, you could snag a high-mileage T8 Twin Engine S60 for under $15,000. However, a couple of grand more should get you better, lower mileage models. That's a good deal for a car that can do a 0-to-60-mph run in under 4.5 seconds. Also, 2019 and newer Volvo S60s got the new design treatment, so an S60 with the "Thor's Hammer" headlights definitely counts as a win.

Cadillac uses the V moniker to define its sporty models. The STS-V arrived in 2006, and unlike the first-gen CTS-V, which used a 400-horsepower Corvette V8 engine, it got a 4.4-liter supercharged Northstar V8 engine. With outputs of 469 horsepower and 439 pound-feet of torque, the STS-V was the most powerful Cadillac of its era. The STS-V also more power than the 911 Turbo of its time. It was larger than the CTS-V and differentiated itself from the normal STS with a power dome hood, wire mesh grille, sportier bumper, a bigger rear spoiler, and larger 10-spoke alloy wheels. Mechanically, it was sportier as well, with a stiffer suspension setup, larger Brembo brakes, a rear differential cooler, Pirelli run-flat tires, and a quicker steering rack.

It received a facelift in 2008, which added a larger grille, vents on the fender, and a mildly refreshed cabin. One year later, Cadillac dropped the STS-V. In 2011, the Northstar V8 engine was discontinued, and with it, the STS as well.

Today, given its age, finding a used Cadillac STS-V below the $15,000 mark should be relatively easy. While its 469-horsepower output is good enough for a 4.6-second 0 to 60 mph time, with just a few upgrades, you can easily unlock 500 horsepower, according to owners.