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 Opel-engineered powertrain under the hood, a 4-cylinder, 16-valves 147hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 193hp 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. 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, still it doesn't help us solve our dilemma, does it? On the other hand, if we'd like to consider vehicle mass in this context too, which we definitely should, SLK offers a potentially life-saving difference of 48% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that Opel does have a slight advantage, all the models observed together. These are the results of an independent reasearch, while our visitors describe reliability of Opel with an average rating of 4.2, and models under the Mercedes Benz badge with 4.4 out of 5. Unfortunatelly, I don't have enough insight that would allow me to comment in more details on the specific models level. That apart, owners of different cars powered by the same engine as Speedster rank it on average as 4.2, while the one under the competitor's bonnet gets 5.0 out of 5.

Opel is undoubtly more agile, reaching 100km/h in 1.3 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 217 kilometers per hour, 23km/h less than the other car. When it comes to fuel economy the winner has to be Speedster, averaging around 8.5 liters of fuel per 100 kilometers (33 mpg), in combined cycle. We can't ignore that 15% difference compared to SLK.

Mercedes Benz 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. From there things take a different direction, with Opel being considerably quicker, thus putting more smile on driver's face. To make things even better, it consumps less fuel! It's really tough to make a final decision here, but if I'd need to, I'd say Mercedes Benz. 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™, among thousands of similar, yet so different vehicles.