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 4-cylinder, 16-valves 150hp unit, while the other one gets its power and torque from a 4-cylinder, 16-valves 200hp 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. That aside, let's consider some other aspects which affect safety. 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. 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 31% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that Opel does have a slight advantage, at least on all of the models level. These are the results of an independent reasearch, while our visitors describe reliability of BMW, as well as Opel, with the same average rating of 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. Above it all, drivers of cars with the same engine as BMW Z4 rank it on average as 4.3 out of 5, exactly the same as the other one.

Opel is way more agile, reaching 100km/h in 3.3 seconds less than its competitor. In addition to that it accelerates all the way to 243 kilometers per hour, 23km/h more than the other car. When it comes to fuel economy the winner has to be BMW Z4, averaging around 7.5 liters of fuel per 100 kilometers (38 mpg), in combined cycle. We can't ignore that 13% difference compared to Speedster.

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. From there things take a different direction, with Opel outracing its opponent in any situation possible, making it better choice for boy racers. It does come at a cost though, and that's the fuel consumption... 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™, among thousands of similar, yet so different vehicles.