It shall be an affirmative defense to claims under this article that: (1) An alleged nonconformity does not substantially impair such use and market value; or (2) A nonconformity is the result of abuse or neglect or of modifications or alterations of the farm tractor not authorized by the manufacturer. 550 10-1-817 SELLING/OTHER TRADE PRACTICES History. Code 1981, § 10-1-817, enacted by Ga. L. 1991, p. 419, § 1.