What is a sleeper car? In our own words, we'd describe a sleeper car as a rather ordinary-looking vehicle with an unexpected amount of power. One of the coolest American sleeper cars of all time is the 1987 Buick GNX. Despite its boring exterior, the GNX hides a turbocharged V6 under its hood with 276 hp and 360 lb-ft of torque allowing it to do 0-60 mph in just over 4 seconds. But that's enough talking about American muscle cars.
Today we're highlighting some of the best European sleeper cars of all time. Some of these used German performance cars are so exquisite that we'd buy them over a Corvette any day. So, without further ado, let's get to the most awesome Euro sleepers that we'd take over an American muscle car any day of the week.
10 Volvo 850 R
Most people still consider Volvo to be an automotive brand catered toward retired folks and broke teens. However, that simply isn't the whole truth. Today we'll be talking about two different Volvos, but first up we have the uber-cool Volvo 850 R. The Volvo 850 R is one of the fastest sports cars from regular car brands the world ever got to lay its eyes on.
Underneath its boxy body was a turbocharged 2.3-liter inline-five engine that made 247 hp and 258 lb-ft of torque. Although the 850 R was a front-wheel-drive sedan or wagon, it still managed to reach 60 mph from a dig in about 6 and a half seconds and topped out at 155 mph.
9 BMW M550i xDrive
We all know that the BMW M5 features one of the greatest V8 engines ever found in a sports car, that's no secret. However, there is one alternative to the famous M5 that's often overlooked by enthusiasts despite having similar performance figures, the BMW M550i. At face value, the M550i looks identical to the standard 5-Series apart from some different trim pieces, but underneath the hood lies something rather familiar.
A twin-turbocharged 4.4-liter V8; a slightly detuned version of BMW's legendary S63 V8. Pumping out 456 hp and 479 lb-ft of torque, the xDrive M550i can reach 60 mph from a standstill in 4 seconds flat. On top of being more luxurious and affordable than the M5, the M550i is a better sleeper car too.
8 Audi RS2 Avant
We all love a fast wagon now, don't we? Especially ones built by Audi. But the Audi RS2 Avant wasn't solely built by Audi. The RS2 was a joint venture between Porsche and Audi, hence the subtly scatted Porsche logos and Stuttgart badges.
Hiding underneath the RS2 Avant's hood was a turbocharged 2.2-liter inline-five resembling the five-cylinder engine found in the modern-day RS3. The RS2 had 311 hp and 302 lb-ft of torque at its disposal and could complete a 0-60 mph run in as little as 5.4 seconds.
7 Mercedes-Benz CL600
Nowadays, Mercedes-Benz strives to deliver the perfect balance between performance and luxuriousness with its products, but the C125-generation CL600 was the one that did it first. If you have your peeled, you might notice the V12 badge on the front fenders of the CL600, but otherwise, you'd never expect there was one lurking underneath its massive hood.
Yes, that's right. The Mercedes-Benz CL600 featured a naturally-aspirated 5.8-liter V12 that pumped out 362 hp and 390 lb-ft of torque. Although it was heavy, the CL600 could achieve a 0-60 mph time of only 4.5 seconds but had a governed top speed of 155 mph.
6 Audi S8
We've already spoken about one fast Audi wagon, and the second is yet to come. For now, let's focus on the best sports sedan money can buy if you're looking to fly under the radar in opulence. Behold, the latest Audi S8. Powering the Audi S8 is a twin-turbocharged 4.4-liter V8 engine that musters out 563 hp and 590 lb-ft of torque.
Through Audi's impeccable Quattro all-wheel-drive system, the S8 can reach 60 mph from a stop in only 3.8 seconds, making it the quickest car on our list yet. Unfortunately, S8 models typically aren't the most reliable cars ever, so if you want a luxury car for daily use, look elsewhere.
5 Volvo V60 T8 Polestar Engineered
What a crazy evolution the Volvo brand has gone through, don't you think? From boring old boxy cars to stunning vehicles with razor-sharp lines, Volvo really made a name for itself. It's such a shame that their performance reputation didn't evolve along with it. But maybe it's not all bad...
Since many people still believe Volvos are for grey-haired grandpas and grandmas, they'd never expect a Volvo station wagon to reach 60 mph from a dig in nearly 4 and a half seconds. That's due to the Volvo V60 T8 Polestar Engineered's hybrid-assisted turbocharged 2.0-liter four-cylinder engine that puts out 415 hp and 494 lb-ft of torque to all four wheels.
4 Vauxhall Lotus Carlton
Back in the day, everyone in the UK knew exactly what the Vauxhall Lotus Carlton was, but still, they struggled to differentiate it from other Carlton cars... and so did the police. As a result, criminals' favorite getaway vehicles were in fact the Lotus Carlton.
As its name suggests, the Vauxhall Lotus Carlton received some modifications from Lotus by boring out the engine and adding forced induction into the mix. The Vauxhall Lotus Carlton had one of the most bulletproof inline-six engines ever made, a 3.6-liter twin-turbocharged straight-six with 377 hp and 419 lb-ft of torque. In the real world, this meant 0-60 mph happened in 5.2 seconds, and it only ran out of breath when approaching 177 mph.
3 Alfa Romeo Giulia Quadrifoglio
Yes, the Alfa Romeo Giulia is a beautiful car, and yes the Quadrifoglio isn't necessarily a "slow-looking car", but its looks definitely understate its performance. After all, the Alfa Romeo Giulia Quadrifolgio features one of the best V6 engines made, a 2.9-liter twin-turbocharged V6 called the 690T.
The Giulia QV's V6 generates 503 hp and 442 lb-ft of torque, which lines it up perfectly with the current BMW M3 and Audi RS4. When the accelerator pedal gets mashed to the floor, the Alfa Romeo Giulia Quadrifolgio reaches 60 mph from stationary in only 3.9 seconds.
2 Audi RS6 Avant
The best sleeper wagon you can buy is the Audi RS6 Avant. Although there were faster versions of the RS6 than the C6-generation we choose, none come near to how special it was. We mean, the C6 Audi RS6 featured a Lamborghini-derived V10.
The C6 RS6's engine was more powerful than the Lamborghini Gallardo it was lent from due to the RS6's 5.0-liter V10 featuring two turbochargers. This caused the V10 engine to produce 571 hp and 479 lb-ft of torque, and the 4,630-lb RS6 did 0-60 mph in 3.9 seconds.
1 BMW E39 M5
As we've previously stated, the BMW M5 is one of the best sleeper cars out there, but the E39 M5 is the all-time best sleeper. Why? Despite the E39 M5 having much faster successors, the E39-generation looks much more understated than its brothers and was also the last BMW M5 to feature a naturally-aspirated V8 engine.
Underneath the E39 M5's hood hides a 4.9-liter V8 engine with 395 hp and 368 lb-ft of torque. On top of its V8 sounding symphonic, the M5 could put its power down rather well through a 6-speed manual and do 0-60 mph in about 4.5 seconds. We'd choose a BMW E39 M5 over an American muscle car any day of the week.
Sources: Ultimate Specs, Acceleration Times