employees shall be compensated at rates consistent with those for employees holding comparable positions in the judicial branch. (e) Preference eligibles In making appointments under subsections (a) through (c), preference shall be given, among equally qualified persons, to persons who are preference eligible (as defined in section 2108(3) of title 5, United States Code). (f) Experts and consultants The Immigration Courts may procure the services of experts and consultants as provided under section 3109 of title 5, United States Code. 4. Budget and expenditures (a) Court budget For each fiscal year, the budget of the Immigration Courts shall be established by the Immigration Courts, without review or modification by the executive branch, and shall be included in the budget of the President as submitted. (b) Permissible court expenditures (1) The Immigration Courts may make such expenditures (including expenditures for personal services and rent at the seat of Government and elsewhere, and for law books, books of reference, and periodicals) as may be necessary to execute efficiently the judicial and administrative functions vested in the Courts. (2) The Immigration Courts may receive and expend funds appropriated to the Courts for purposes of paragraph (1) either— (A) directly, or (B) by transfer to— (i) the Director of the Administrative Office of the United States Courts, (ii) another court established under article I of the Constitution, or (iii) an executive agency as defined in section 105 of title 5, United States Code, to cover the expense of such administrative support and guidance (including budgetary and financial, payroll and personnel, protective and security, recordkeeping and statistical, and information technology services) as the Court may request and the Director, court, or agency may agree to provide from time to time. (c) Method and source of expenditures All expenditures of the Immigration Courts shall be allowed and paid upon presentation of itemized vouchers signed by the certifying officer