Okay, I've uploaded an hotfix for the map (same download link )
-fixed shadows, fogs, soundscape
-fixed unwalkable edge in the blue ramp in central area.
-fixed gap on thouse visualizers
I've been through optimization process in the central area : smaller lightmaps, nodrawed hidden surfaces, faded props, area portals. Didn't get a miracle, but you can expect ~20% fps increase in worst cases.
I fear that getting higher perf would require a layout modification, as there is very little rendered content that shouldn't.
Thanks Hellfire for your support.