Total 17 interior's:

10 empty apartment shells for the creativity of your players
High-end corridor (75 floors total) with 12 doors on each floor
Mid-end corridor (40 floors total) with 12 doors on each floor
Low-end corridor (separate options for 1, 2, 3, 4 and 5 floors, respectively, ideal for poor areas)

The interiors have been tested on a real server, the players are happy and have not reported any performance issues.

Bonus: 105 props available for placement in your players' unique interiors (including lighting, furniture and decorations)