Hey!
Those buildings look great.
A few tips:
Darken/or lighten (preferably darken) the ambience. Set it to around 4 for all colors, then manually lightmap where you have street lights, etc., because the dark ambience will add a depth to the city, that in reality isn't there, and will also improve the gameplay, and will make the player think "Wow, I want to
explore!
Just a tip.
Also, give an entity a sound to admit (like one of those buildings, assuming those aren't segments) of a city ambience. Whether it's wind, or cars and people. That was also improve the ambience. Alot.
-AaronG
Good luck with this!