It's meant to be slightly humourous. I don't know exactly if he meant to use the term "Germanic" like it was a bad thing, he might have only intended to say that it is German, but after all this was the car originally dreamt up by Hitler to be the "people's car". Even if he did mean it in a slightly xenophobic way, this would not be unacceptable in Britain and a lot of people are still amused by this kind of humour (as long as it's relatively harmless)

At the end of the day, it's an opinion. The Beetle is a cult car and I think the author is just rebelling against this because he doesn't buy into its cult appeal enough to overlook its flaws. I think he gives a fair explanation for why he dislikes it (noisy, uncomfortable and faulty), when he says it's slow that may be a fair comment because this car stayed around for years and it's lack of speed probably became more and more obvious and as newer cars came along. People don't usually want a car to be slow and unable to keep up with the rest of the traffic.

When he says the engine's in the wrong place, that is a joke, he really means he thinks the design is awkward.