Yes, of course. The limit was set, simply to prevent accidental over-generation of floors. Potentially slowing down the view-port (depending on your computer). If you are new to geometry nodes, full instructions on how change these, are in the PDF-manual (its very easy).

No.. unless your computational power rivals Pixar's. The towers are well detailed; and have interiors and real lights in all the units. The more towers there are in a scene, the more calculations Blender has to make.