Question of the Week: What’s your favorite sleeper performance car?

A sleeper car is one you wouldn’t expect to leave a snarling exotic car in its wake at the stoplight or dragstrip. Following Teddy Roosevelt’s mantra of speaking softly but carrying a big stick, they keep their impressive horsepower hidden until it’s called upon.

Many factory-produced cars fit the sleeper mold. For example, muscle cars put big power in a lighter package, and the same ethos is what gave us the entire hot-hatch category. With either genre, people in the know came to expect solid performance from these cars and they know what to look for—maybe it’s the telltale hood scoop, big brake discs, or dual exhausts that hint at what’s really going on under the hood.

Many muscle cars were so ostentatious there was no way of hiding their performance potential, while other, similar trim levels offered just as much power but kept the plain wrapper.

The concept of a sleeper car goes back decades, but some current production cars fit the mold too. While enthusiasts know about the 707-horsepower Jeep Grand Cherokee Trackhawk, it blends in with the garden-variety Jeeps. And the LS3-powered Chevrolet SS could be mistaken for a Malibu (and often is).

So let’s hear it in the comments: What was the best sleeper car that ever rolled off a production line? If modification is more your speed, show us your home-grown sleeper car that the manufacturer never built.