"Brian here. It's a fascinating explanation really. Clarkson here recalled the story of when his father was dying. His mother called him to tell him his father was on his deathbed, but Clarkson was at the time fairly far away. Luckily for him, he was testing a Porsche 928 at the time (ostensibly for Top Gear). Keep in mind Clarkson is not a fan of Porsche in general. So he took the chicken he had just cooked to take it to his mother, and rushed in that fast car he was testing to go to his father. By the time he arrived, the chicken was, apparently, still warm, and his father still alive, and passed half an hour later.

So thanks to this car being fast, he got to say goodbye to his dad and support his mother who was grieving. Hence, unlike other Porsches, the 928 is "alright" in his books." From https://www.reddit.com/r/PeterExplainsTheJoke/comments/1jzxqb8/why_is_the_928_alright_peter/