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 265hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 231hp 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, SLK offers a marginal difference of 4% 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, at least on all of the models level. 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. The same official information place Z4 as average reliability-wise, and SLK is more or less at the same level.Above it all, drivers of cars with the same engine as BMW Z4 rank it on average as 4.8, while the one under the competitor's bonnet gets 4.0 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.6 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 250 kilometers per hour, exactly the same as the other car does. When it comes to fuel economy the winner has to be BMW Z4, averaging around 8.6 liters of fuel per 100 kilometers (33 mpg), in combined cycle. We can't ignore that 13% 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, BMW Z4 offers much better overall protection, which launches it ahead of the other contender. It all continues in the same direction, with BMW offering somewhat better performance, just enough to call it quicker. 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. Anyway, that's the most objective conclusion I could've came up with and it's based solely on the information found on this website. Aspects such as design, practicality, brand value and driving experience are there for you to measure them out. 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.