Modifies GS 162A-203, applying only to the City of Winston Salem, to add new subsection (c) allowing local government units (LGUs) or a joint agency created pursuant to GS 160A-461(permitting interlocal cooperation) to exempt affordable housing developments from or reduce the cost of a system development fee imposed by GS Chapter 162A, Article 8. Requires the LGU or joint agency to adopt criteria for determining whether a development qualifies for the exemption or reduction.