shall not be considered employees of the United States Government;

shall be appointed without regard to the provisions of title 5 governing appointments in the competitive service; and

may be paid without regard to chapter 51 and subchapter III of chapter 53 of title 5, except that an officer or employee may not be paid more than 15 percent above the annual rate of basic pay for level GS–15 of the General Schedule under section 5107 of title 5.