The Governor may enter into reciprocal agreements on behalf of the Commonwealth with the appropriate authorities of any state of the United States with respect to all taxes imposed by the Commonwealth and by any other state of the United States on motor vehicles, the operation of motor vehicles, or any transaction incident to the operation of motor vehicles. Except as provided in this section, all agreements entered into by the Governor with respect to any subject of reciprocity as to which provision is expressly made by statute shall conform to the provisions of that statute. As to any other subject of reciprocity appropriate to the powers vested in the Governor by this section, the Governor may agree to whatever terms and conditions as in his judgment are best calculated to promote the interests of the Commonwealth. Except as provided in this section, it is the policy of the Commonwealth to grant reciprocity to the residents of another state when that state grants reciprocity to the residents of the Commonwealth. All agreements entered into by the Governor pursuant to this section shall be reduced to writing, and a copy shall be furnished to the Secretary of the Commonwealth and the Superintendent of State Police.