This act shall apply to all municipalities, special fire control districts, chapter plans, local law municipalities, local law special fire control districts, or local law plans presently existing or to be created pursuant to this chapter. Those plans presently existing pursuant to s. 175.351 and not in compliance with the provisions of this act must comply no later than December 31, 1999. However, the plan sponsor of any plan established by special act of the Legislature shall have until July 1, 2000, to comply with the provisions of this act, except as otherwise provided in this act with regard to establishment and election of board members. The provisions of this act shall be construed to establish minimum standards and minimum benefit levels, and nothing contained in this act or in chapter 175 shall operate to reduce presently existing rights or benefits of any firefighter, directly, indirectly, or otherwise.