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 coupe 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 620hp unit, while the other one gets its power and torque from a 6-cylinder, 24-valves 343hp 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, still it doesn't help us solve our dilemma, does it? Furthermore, if we'd like to consider vehicle mass in this context too, which we definitely should, 911 offers a marginal difference of 4% 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 3.7, 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 911 rank it on average as 3.0 out of 5, exactly the same as the other one.

Porsche is undoubtly more agile, reaching 100km/h in 1.5 seconds less than its competitor. In addition to that it accelerates all the way to 330 kilometers per hour, 80km/h more than the other car. When it comes to fuel economy things look pretty much the same for both cars, averaging around 12 liters of fuel per 100 kilometers (24 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 much better overall protection, which launches it ahead of the other contender. From there things take a different direction, with Porsche being considerably quicker, thus putting more smile on driver's face. To make things even better, it consumps less fuel! It's really tough to make a final decision here, but if I'd need to, I'd say 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. 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.