Agree 100%. This is earnest advice. It may seem like a snarky quip, but it's not. This is dead serious:
Never use a car analogy. Never.
Cars are too intimate. This is especially endemic to American culture. Too many people identify with their car. You may intend to contrast the horsepower of one car to another, but the reader will inevitable contrast the values most dear to them. "A coupe versus a saloon! HOW DARE YOU!?!?!"
