Funds appropriated under authority of this chapter may be used for the purchase or hire of passenger motor vehicles, for printing and binding, for rent and personal services in the District of Columbia and elsewhere without regard to the limitation contained in section 607(g) of the Federal Employees Pay Act of 1945, as amended [
5 U.S.C. 947
(g)], and for the employment of experts or consultants or organization thereof, on a temporary basis, by contract or otherwise, without regard to chapter
51 and subchapter
III of chapter
53 of title
5, at rates not in excess of $50 per diem.