(1) Parts 1-4 of this chapter are intended to afford an alternative method for the making or acquisition of improvements by a municipality, the creation of special improvement districts for central business districts of the various municipalities, the levy of assessments and the issuance of bonds by municipalities, and shall not be so construed as to deprive any municipality of the right to make or acquire improvements, create special improvement districts, levy the assessments or other special taxes or issue bonds under authority of any other law of this state now in effect or hereafter enacted, including part 5 of this chapter. Nevertheless, parts 1-4 of this chapter shall constitute full authority for the making or acquisition of improvements, creation of central business improvement districts, levy of assessments and issuance of bonds under title 9, chapter 21, to the extent applicable, by such municipalities as act under parts 1-4 of this chapter.
(2) No act hereafter passed by the general assembly amending other acts relating to the same subject matter as covered by parts 1-4 of this chapter shall be construed to affect the authority to proceed under parts 1-4 of this chapter in the manner provided in parts 1-4 of this chapter, unless such future act amends parts 1-4 of this chapter and specifically provides that it is to be applicable to proceedings taken and to bonds issued under parts 1-4 of this chapter.