Auto immune

Someone who tragically does not understand the appeal of sexy, fast cars.

I love the new BMW convertible but my husband is Auto Immune and drives a boring SUV.

auto-immune disorder

An serious illness characterized by the inability to resist the allure of motor vehicles, whether it's buying more cars than you need, needlessly driving/riding in them for extended periods of time, tinkering/upgrading them unnecessarily, etc.

Tim The Tool-man couldn't resist driving his wife's antique Austin-Healey sports car even though she'd expressly forbidden him to touch it. He admits that he has auto-immune disorder --- he's thinking of checking into the Henry Ford Clinic. :P