Well, these are two pretty similar cars we have here! It's only details that could potentially make the difference. Considering they both belong to the sports car segment and utilize the same 2-door cabriolet body style and the rear wheel drive system, it all comes up to the specific petrol engine choice they offer. The first one has a BMW-engineered powertrain under the hood, a 6-cylinder, 24-valves 231hp unit, while the other one gets its power and torque from a 6-cylinder, 18-valves 218hp engine designed by Mercedes Benz.

The fact that the BMW got tested by the European New Car Assessment Programme (Euro NCAP), while the other contender didn't, offers a slight advantage, as the 4-star rating is better than none. Moving further on, let's take a closer look at some additional safety-related facts. Both vehicles belong to the sports car segment, which is generally classifying them somewhere in the middle safety-wise, but it doesn't do much to help us decide between the two. On the other hand, taking kerb weight as an important factor into account, CLK offers a considerable difference of 26% more metal.

Reliability is not the best thing to consider on the make level, but it is worth mentioning that both brands display similar results in faults and breakdowns, when all the models are taken into account. That's the official data, while our visitors describe reliability of BMW with an average rating of 4.1, and models under the Mercedes Benz badge with 4.3 out of 5. The same official information place Z4 as average reliability-wise, and CLK is more or less at the same level.That apart, owners of different cars powered by the same engine as BMW Z4 rank it on average as 5.0, while the one under the competitor's bonnet gets 4.6 out of 5.

BMW is undoubtly more agile, reaching 100km/h in 2.3 seconds less than its competitor. In addition to that it accelerates all the way to 250 kilometers per hour, 10km/h more than the other car. When it comes to fuel economy the winner has to be BMW Z4, averaging around 9.1 liters of fuel per 100 kilometers (31 mpg), in combined cycle. We can't ignore that 20% difference compared to CLK.

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, BMW Z4 offers significantly better overall protection, taking the lead here. It all continues in the same direction, with BMW outracing its opponent in any situation possible, making it better choice for boy racers. To make things even better, it consumps less fuel! All together, there's not much more to say, in this case I wouldn't even consider anything but 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. In case you have two minutes to spare I invite you to define your needs, desires and budget and see which car would be chosen by the virtual adviser™, out of 12.000+ vehicles we currently have in our database.