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 375hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 340hp 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. 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, still it doesn't help us solve our dilemma, does it? On the other hand, taking kerb weight as an important factor into account, BMW Z4 offers a marginal difference of 8% more metal.

Manufacturers have been building their reliability reputation for decades now and, generally speaking, it appears that BMW does have a slight advantage, all the models observed together. These are the results of an independent reasearch, 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. Above it all, drivers of cars with the same engine as Boxster rank it on average as 3.0 out of 5, exactly the same as the other one.

Porsche is a bit more agile, reaching 100km/h in 0.3 seconds less than its competitor. In addition to that it accelerates all the way to 290 kilometers per hour, 40km/h more than the other car. When it comes to fuel economy the winner has to be BMW Z4, averaging around 9 liters of fuel per 100 kilometers (31 mpg), in combined cycle. We can't ignore that 10% difference compared to Boxster.

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 slightly better overall protection and takes the lead. From there things take a different direction, with Porsche offering somewhat better performance, just enough to call it quicker. It does come at a cost though, and that's the fuel consumption... 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. 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.