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 192hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 147hp engine designed by Opel.

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 that fact doesn't break the tie between the two cars. Furthermore, if we'd like to consider vehicle mass in this context too, which we definitely should, BMW Z4 offers a potentially life-saving difference of 45% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that Opel does have a slight advantage, 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 Opel badge with 4.2 out of 5. Unfortunatelly, I don't have enough insight that would allow me to comment in more details on the specific models level. We should definitely mention that owners of cars with the same powertrain as BMW Z4 rank it on average as 2.8, while the one under the competitor's bonnet gets 4.2 out of 5.

Opel is undoubtly more agile, reaching 100km/h in 1.1 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 217 kilometers per hour, 18km/h less than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 8.7 liters of fuel per 100 kilometers (32 mpg), in combined cycle.

Opel 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 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. Speedster still consumps less fuel, which needs to be taken into consideration. It's not difficult to say then that if I'd need to make a choice, it would definitely be the 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. 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™, among thousands of similar, yet so different vehicles.