One could make this comparison between a car and any woman, and God knows that has been done many times before, but I don't think it is appropriate. For one thing, women of any kind are not actually objects. No one should "own" them, unless they want to be. The "woman as a car" makes more sense with a certain type of woman (or man); the type that is happiest when pleasing their... driver... The sort that finds great satisfaction in the attention of, and being of great value to, another. I'm not making a value judgment about other types of people. There is room for everyone and viva la difference. But a good slave... ahh....
A good slave is like a fine car: Sometimes you just want to drive it, maybe to release tension after a long day, or maybe just for the pure joy of driving. You're proud of your car, you enjoy it, you picked the one you did for its looks and the way it handled.
When you take it out, you aren't gentle with it... you drive it as hard as you can. You burn some rubber off the tires and you rev the engine so it gets really nice and hot under the hood. You don't worry if it's going to get a little dirty or wet; you know it will clean up well later. The car is there for you to use. This is the purpose of a car, what the car was made for, and the car knows it.
On the other hand, you do NOT push your baby further than it can handle. You don't want to wreck it or end up stranded without a ride, right? And you may not be thinking about how your ride feels or whether or not the drive is as good for it as it is for you while you scream around the corners, but you do take care of her needs. If she is running low on gas, you take the time to stop and fill up. And you want to know when she needs that. It wouldn't be good if the gas gauge stuck and failed to let you know it was running empty. You need for your car to let you know when something is going wrong. You keep an eye on the gauges and you trust that the gauges are providing an accurate indication of how things are working. You might just have one red "check engine" light or an entire series of dials and gauges that tell you every detail of internal operation. But you also listen; is there a groan that doesn't sound right? is the clutch slippery? Are the gears meshing right?