Can I report my car as stolen if my wife took my car?

You can report it as stolen, but then you would be telling something less than the truth. That is never a good idea when dealing with law enforcement or the courts: you are free to keep your mouth shut, but you are not free to lie. If you live in a marital (=community) property State, your wife likely has a one-half interest in the vehicle regardless of whose name is on the title. Why not move the separation or divorce action forward, and seek an Order awarding you the car? Retain a good family law attorney: it's almost always worth the investment.

No. Just because it's in your name doesn't mean it isn't community property. You can make a motion to the family court to allow you use of that car if you have no other.

You're still married so the vehicle is community property. You call the car in stolen, and there is no order that it is yours, this could lead to potential problems in your family law case. Especially if she is working and now had no ability to get back and forth. If you have two cars, and she has none, think of how this would look to the judge. I would bring this to the attention to your judge in the divorce case if it's bothering you that much, but greed and back biting is never a good thing.

No, if you ever gave her permission to use the car while you were married, then it is not theft. It is an issue to be dealt with during the divorce proceedings. If you don't have an attorney, you should get one.

No, Wisconsin is a marital property state, she has equal rights to the car until a court says otherwise. File for divorce and a temporary order. Ask the court to make her give back the car.