Two significantly similar cars, no doubt about that. Still, each one has something different to offer. Having both cars powered by diesel 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 6-cylinder, 24-valves 218hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 225hp engine designed by Audi.

Both vehicles got tested by European New Car Assessment Programme (Euro NCAP), with the Audi being a slightly better choice apparently. Still, apart from the official crash test results there are other things we need to be aware of. 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 11% 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, when all the models are taken into account. These are the results of an independent reasearch, while our visitors describe reliability of BMW with an average rating of 4.1, and models under the Audi badge with 4.2 out of 5. Independent research findings rank 5 Series 23% below average, and A6 20% below the first one. That apart, owners of different cars powered by the same engine as 5 Series rank it on average as 5.0, while the one under the competitor's bonnet gets 4.7 out of 5.

Both of the cars accelerate exactly the same, so we couldn't put one above the other. Car No. 1 reaches top speed of 245 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy the winner has to be 5 Series, averaging around 6.9 liters of fuel per 100 kilometers (41 mpg), in combined cycle. We can't ignore that 14% 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. When it comes to performance, both vehicles provide similar experience, so I wouldn't point any of them out. 5 Series , on the other hand, consumps significantly less fuel, and that's a big plus. It's really tough to make a final decision here, but if I'd need to, I'd say BMW. Nevertheless, let's not forget that people have different preferences and needs, so what really counts is your personal feel. I'm only here to help. 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™, out of 12.000+ vehicles we currently have in our database.