I have cars by all the manufacturers you mention. They are all about the same for maintenance. I don’t do a lot of it myself, but the small parts such as spark plug wires, water pumps, belts, tune up parts, fuel pumps, filters, exhausts, brakes, and so forth cost within about 10% or so of each other. Of the 3, the Porsche is easily the best built, obviously the best performer, and has the nicest interior. MB, while certainly very nice is rather pedestrian compared to a Porsche. The nice thing about MB is that it’s relatively easy to find a service technician that isn’t an idiot and a thief. Sadly not the case with Porsche. That’s the reason I have 2 MB’s and after 11 years, am selling my Porsche

…Tracy