hmmmm, smaller pulley huh? have you driven it at all? I would look it over real good if it has a smaller pulley on it and take it for a ride. If the pulley is smaller than a 3.1 then i would make sure the dealership didn't flash it back to stock. But if all checks out 20-21K for a cobra sounds sweet. Specially buy it before the weather gets nice or you can add another $1000-$1500 to the price.