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 315hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 306hp engine designed by BMW.

Unfortunatelly, neither of the two vehicles was submitted to the European New Car Assessment Programme (Euro NCAP) testing. This makes it virtually impossible for me to pick one over the other and I'm generally against buying such cars as the safety should really always come first. 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. On the other hand, taking kerb weight as an important factor into account, BMW Z4 offers a considerable difference of 10% more metal.

I don't like generalizing things when it comes to reliability, although it does seem that BMW does have a slight advantage, all the models observed together. That's the official data, while our visitors describe reliability of Porsche with an average rating of 3.9, and models under the BMW badge with 4.1 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 Boxster rank it on average as 3.0, while the one under the competitor's bonnet gets 4.0 out of 5.

Porsche is a bit more agile, reaching 100km/h in 0.1 seconds less than its competitor. In addition to that it accelerates all the way to 279 kilometers per hour, 29km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 9.2 liters of fuel per 100 kilometers (31 mpg), in combined cycle.

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 significantly better overall protection, taking the lead here. From there things take a different direction, with Porsche outracing its opponent in any situation possible, making it better choice for boy racers. To make things even better, it consumps less fuel! No mistake, whatever you decide here, but I'd still go for the Porsche. Nevertheless, let's not forget that people have different preferences and needs, so what really counts is your personal feel. I'm only here to help. 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.