According to the paper the study involved 200 subjects, a relatively small sample size. It's also true that many social science papers, perhaps even up to 50%, aren't replicable. Nevertheless, Freud was right about a great deal, it's certainly possible he was also right about this
"Aha, you have a powerful car/pick-up truck? I'm now thinking about your genitals!"
https://futurism.com/neoscope/sports-cars-penis-size