In the Special Downtown Jamaica District, the use regulations of the underlying district shall apply except as modified in this Section, inclusive. The use regulations of the underlying C4-5X, C6 and M1-4 Districts relating to public parking garages are modified in Section 115-11. The use regulations of the underlying C6-4 District relating to Use Group 11B, are modified in Section 115-12. Special ground floor use and transparency regulations shall apply in the C4-5X and C6 Districts pursuant to Sections 115-13 (Ground Floor Use, Frontage and Major Building Entrance Regulations in C4-5X and C6 Districts) and 115-14 (Transparency Requirement in C4-5X and C6 Districts). The use regulations of the underlying M1-4 District, including Use Groups 3, 4, 6, 10, 16, 17 and 18, are modified as specified in Section 115-15.