Laser
You may want to read up on your state laws. The use of deadly force to protect your car would prolly end up with you in the jail. Having just read them.
Have a link to help you out. (c) Limitations on justifiable use of force.--
The use of force is justifiable under this section only if the actor first requests the person against whom such force is used to desist from his interference with the property, unless the actor believes that:
such request would be useless;
it would be dangerous to himself or another person to make the request; or
substantial harm will be done to the physical condition of the property which is sought to be protected before the request can effectively be made.
The use of force to prevent or terminate a trespass is not justifiable under this section if the actor knows that the exclusion of the trespasser will expose him to substantial danger of serious bodily injury.
The use of force to prevent an entry or reentry upon land or the recaption of movable property is not justifiable under this section, although the actor believes that such reentry or caption is unlawful, if:
the reentry or recaption is made by or on behalf of a person who was actually dispossessed of the property; and
it is otherwise justifiable under subsection (a)(2).
The use of deadly force is justifiable under this section if:
(A) there has been an entry into the actor's dwelling;
(B) the actor neither believes nor has reason to believe that the entry is lawful; and
(C) the actor neither believes nor has reason to believe that force less than deadly force would be adequate to terminate the entry.
If the conditions of justification provided in subparagraph (i) have not been met, the use of deadly force is not justifiable under this section unless the actor believes that:
(A) the person against whom the force is used is attempting to dispossess him of his dwelling otherwise than under a claim of right to its possession; or
(B) such force is necessary to prevent the commission of a felony in dwelling.
So from that page, deadly force in protection of propertie only applies to dwellings not cars.