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 Porsche-engineered powertrain under the hood, a 6-cylinder, 24-valves 255hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 265hp engine designed by BMW.

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, taking kerb weight as an important factor into account, Boxster offers a considerable difference of 10% more metal.

Reliability is not the best thing to consider on the make level, but it is worth mentioning that BMW does have a slight advantage, at least on all of the models level. These are the official statistics, while our visitors describe reliability of Porsche with an average rating of 3.7, and models under the BMW 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 Boxster rank it on average as 3.0, while the one under the competitor's bonnet gets 4.8 out of 5.

BMW is a bit more agile, reaching 100km/h in 0.2 seconds less than its competitor. Still, it lacks the power to win the top speed competition, topping at 250 kilometers per hour, 13km/h less than the other car. 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 9% difference compared to Boxster.

BMW is apparently more reliable, not too much, but just enough. 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 significantly better overall protection, taking the lead here. 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. 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. I suggest you spend two more minutes in order to find out which car, based on your needs and budget, would be picked by the virtual adviser™, out of 12.000+ vehicles we currently have in our database.