Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by petrol engines and utilizing the 4-door sedan body style within the same 'Luxury car' segment, the only major difference here really is their wheel drive configuration (rear for the BMW and 4 x 4 in the case of the Audi). The first one has a BMW-engineered powertrain under the hood, a 8-cylinder, 32-valves 367hp unit, while the other one gets its power and torque from a 10-cylinder, 40-valves 435hp engine designed by Volkswagen.

Both vehicles got tested by European New Car Assessment Programme (Euro NCAP), with the Audi being a slightly better choice apparently. Moving further on, let's take a closer look at some additional safety-related facts. Both vehicles belong to the luxury car segment, which is generally a very good thing safety-wise, but that fact doesn't break the tie between the two cars. On the other hand, if we'd like to consider vehicle mass in this context too, which we definitely should, Audi A6 offers a considerable difference of 17% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that both brands display similar results in faults and breakdowns, all the models observed together. These are the official statistics, while our visitors describe reliability of BMW, as well as Audi, with the same average rating of 4.2 out of 5. The same official information place 5 Series as average reliability-wise, and A6 is more or less at the same level.We should definitely mention that owners of cars with the same powertrain as 5 Series rank it on average as 5.0, while the one under the competitor's bonnet gets 4.0 out of 5.

Audi is a bit more agile, reaching 100km/h in 0.3 seconds less than its competitor. In addition to that it accelerates all the way to 250 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy an obvious choice would be 5 Series, averaging around 11.1 liters of fuel per 100 kilometers (25 mpg), in combined cycle. That's 21% difference compared to Audi A6!

BMW appears just a bit more reliable, although the difference is truly marginal. The most important thing when deciding between any two vehicles should always be safety, both passive and active. In my opinion, everything taken into account, Audi A6 beats the other contender by far, making it the best choice without even considering other things. It all continues in the same direction, with Audi offering somewhat better performance, just enough to call it quicker. It does come at a cost though, and that's the fuel consumption... It's really tough to make a final decision here, but if I'd need to, I'd say BMW. In any case that's my personal view, built upon all the data available to me. What should decide here though is the way you feel about the two vehicles, and I hope you'll find my guidelines useful in the process. Also, you could use the oportunity to find out which car, everything taken into account, would be the perfect choice for you in the eyes of the virtual adviser™, among more than 12.000 different ones in our database.