When we think about luxury cars, we have a very specific image in mind: a car that's very comfortable and silent with smooth, effortless power. These cars are designed to isolate you from the rest of the world when you're inside, turning your commute into a very relaxed experience. The interior of these cars also elevates this experience with posh leather and wood inserts, all meant to enhance comfort and luxury. These are usually powered by big, torquey V8s or big, quiet V12s that move these luxury cruisers with ease.For decades, the German automakers like Audi, Mercedes, and BMW have used this formula to elevate the experience of their luxury cars. But sometimes, engineers decide to try new things. They become a little daring and want to see what happens when they merge the most aggressive engine available with one of the most sensible luxury cars in their fleet. The result, in some cases, is one of the best cars of its era. Audi Has Always Been About Understated Luxury Bring a TrailerAudi is one of those companies that makes cars that aren't flashy but very sophisticated. BMW focuses on vehicle dynamics, hence the "Ultimate Driving Machine" slogan, Mercedes has always been known as the gold standard for luxury cars, always pioneering new tech and safety features. Audi sits in the middle of these brands, with elegant cars that easily match the tech of its rivals. They were the choice for the person who wanted a high-quality, high-tech car that didn’t scream for attention.For years, Audi has always followed this sensible path, and that has made them lag behind even though the cars were just as good. But in the late 2000s, Audi took a bold step that nobody saw coming. Instead of sticking a more powerful V8 in its executive sedan, the engineers decided to take the engine from one of the most iconic supercars in the world and drop it in a four-door sedan. The Audi S6 With The Heart Of A Raging Bull Bring A TrailerThe car of course, is the third-generation C6 Audi S6 (2006-2011). At first glance, it looked like the standard A6 executive sedan that an accountant or lawyer would drive. It had a few engine options ranging from an inline four to a big V8, but when you start the S6, the exhaust note is completely different. The startup sound is the same one you hear from a Lamborghini Gallardo. A rumbling, loud 5.2-liter V10. You may think it's the same engine in the Audi R8, and you're right, but the S6 got the V10 first in 2006 before the R8 got it in 2009.This may come as a surprise, but because Audi owns Lamborghini, it had access to every part available to the Lamborghini. The Gallardo and R8 made well over 500 horsepower and were built for all-out speed and performance. The S6 was a sedan, so the engine was calibrated for that purpose. It was de-tuned to 435 horsepower, but torque remained the same at 398 pound-feet. This engine instantly made this car feel exotic; it was an understated German luxury car with the heart of an Italian masterpiece. The S6 Wasn't The Only Audi Sedan With The V10 Via: AudiThe S6 was the first Audi to get the V10, but it wasn't the only sedan. Audi didn't want to stop there, so this madness was spread across a few cars in the lineup, and some of these were even crazier. The flagship second-generation Audi S8 (D3), introduced in 2006, featured a 5.2-liter V10 engine that produced 450 hp. It was the ultimate sleeper with its understated looks and limousine-looking body but could keep up with most sports cars in a straight line and still produce an exotic engine note. But Audi wasn't done yet.The next car, the Audi RS6, was only ever sold in Europe until recently. The C6 RS6 (2008-2011) came later but took this engine to the max. It didn't use the updated 5.2-liter V10; instead, it used the older and better-sounding 5.0-liter V10 with two turbochargers attached. The result was a terrifying 571 horsepower and 479 pound-feet of torque. This car was more powerful than any Lamborghini Gallardo or Audi R8, as those made peak power at 562 horsepower and 398 pound-feet of torque. But all of them were still slower compared to dedicated supercars. The V10 Made This Car Exotic Among High-End Luxury Cars Audi In the world of high-end luxury cars, the S6 with its V10 was a standout car. As previously mentioned, most top-end luxury cars would use a big, quiet V12 if they wanted more power. A V12 is the ultimate symbol of smoothness and status, but a V10 leans more towards performance. By choosing a V10, Audi moved the S6 into a very exclusive club.At the time, the only other manufacturer was crazy enough to put a V10 in a sedan, and that was BMW with the E60 M5. BMW made a wild but conscious choice with this, as they wanted to bring Formula 1 tech to the streets, and its V10 was inspired by that world. Audi did this to tie its connection to the Lamborghini supercar. The S6 sounded different in every way and was one of the coolest cars, and almost no one else could relate to that special feeling unless you had an M5 or spent way more money to get a supercar. Performance Compared To Its Rivals Via: Bring a TrailerThe Audi was fast, but cars like this are meant to perform really well in a straight line, and the S6 was a beast. With its Quattro all-wheel-drive system, it could launch from 0 to 60 mph in about 5.2 seconds and achieve that consistently. Stack it up against the E60 M5 and W211 E63, and the Audi was slower because those made more power. The M5 had the soundtrack to back up its momentum with its V10 and was also better on track, while the E63 had more low-end grunt from its torquey 6.2-liter V8 (M156). The Audi wasn't the fastest car, but it was usable in every weather and had better high-speed stability. This V10 Powered Car Is Very Affordable Bring A TrailerNothing excites a car enthusiast more than bargain performance cars, and the S6 can be had for such a great price these days. Back when they were new, these cars had an MSRP of $74,000-$78,000, but today you can get them for a fraction of that price. Keep in mind, the original Audi R8 V10 now costs between $60,000 to $120,000, while the Gallardos are higher at $85,000 to $150,000.In the current market, a well-kept Audi S6 with that glorious V10 can often be found between $12,000 and $18,000. Think about that for a second: you can own a luxury sedan with a Lamborghini V10 for the price of a used Toyota Corolla (2014-2017). It is arguably one of the best deals in the automotive world. You get the leather interior, the Bose sound system, and the "Raging Bull" soundtrack for less than the tax on most new luxury cars. They Are Not Cheap To Run Bring A TrailerBut—and this is a very big "But"—there is a reason these cars are so affordable. While they are cheap to buy, they are not cheap to maintain. Maintaining a V10 Audi is like dating a high-maintenance celebrity; it's thrilling, but your bank account will suffer. These are exotic engines, and they suffer from common "exotic" problems. It'll have the same issues and similar repairs to a Lamborghini Gallardo. These common problems include:Carbon Buildup: Because of the direct injection, the intake valves need professional cleaning every 50,000 miles. High Oil Consumption: These engines love oil, so you have to make sure you maintain the optimum oil level and use the recommended brand. Cramped Engine Bay: Because the V10 is so large, almost any major repair requires "dropping the engine," which can lead to thousands of dollars in labor costs alone. If you are looking at one of these cars, the best advice is to treat it like you're buying a high-end exotic. Don't buy the cheapest one you find; buy the one with the best service history. The Audi S6 is a masterpiece of engineering, showing us a time when a sensible German company went a little crazy. It's an exotic car in a business suit, and as long as you can afford the maintenance fee, it remains one of the most exciting cars to commute in for not a lot of money.Sources: Audi, Lamborghini.