sleepers....how fast and how plain before it is one?

Imo a sleeper is a car that does not look like it would be fast nor was it ever intended to be fast. So a stock appearing and sounding 4 door that runs 10s yes it's a sleeper. If it had open exhaust and sound like a NHRA drag car with 12 wide tires even tho its a four door it's not a sleeper. I have seen some really cool sleepers one guy around town had a plain stock appearing s10 with a 327 that would scream he had mufflers and dot street tires looked and sounded like a regular ole 2.2 s10 till he stood on it. I think it ran 8s in the 1/8 I'd call that a sleeper