N.J. Stat. Ann. § 40:55D-53.3

14. A municipality shall not require that a maintenance guarantee required pursuant to section 41 of P.L.1975, c.291 (C.40:55D-53) be in cash or that more than 10% of a performance guarantee pursuant to that section be in cash. A developer may, however, provide at his option some or all of a maintenance guarantee in cash, or more than 10% of a performance guarantee in cash.