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 193hp 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 Mercedes Benz 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. Still, apart from the official crash test results there are other things we need to be aware of. Both vehicles belong to the sports car segment, which is generally classifying them somewhere in the middle 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, SLK offers a marginal difference of 2% 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. These are the official statistics, 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. Some independent research have also placed Z3 as average reliability-wise, and SLK is more or less at the same level.That apart, owners of different cars powered by the same engine as BMW Z3 rank it on average as 5.0, while the one under the competitor's bonnet gets 4.6 out of 5.

Both of the cars accelerate exactly the same, so we couldn't put one above the other. Car No. 2 is faster though, reaching top speed of 245 kilometers per hour, 20km/h more than the other car. When it comes to fuel economy the winner has to be BMW Z3, averaging around 9.4 liters of fuel per 100 kilometers (30 mpg), in combined cycle. We can't ignore that 18% difference compared to SLK.

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, SLK beats the other contender by far, making it the best choice without even considering other things. It all continues in the same direction, with Mercedes Benz being considerably quicker, thus putting more smile on driver's face. It does come at a cost though, and that's the fuel consumption... I believe that, when we take all into account, we have only one winner here - the Mercedes Benz. 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. 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.