Well in hammer i see one thing you have done a bunch of times that can be bad. Yours curves...
You should make them look more like the ones on the right, I counted 10 half circles like this each with 16 slices, you can turn 160 angle brushes (source do not like angle much) into 10 ok ones. Make sure to func_detail them as well, be sure to func_detail the red/blue signs too.
Also if you can figure out your fog (blacks suggestion is nice) you can make the skybox less deep. It's insane deep atm and its just a void, if it were smaller it would help fps alot. Keep the height, lose the depth.
Also the env_sun no longer needs a info target, you can "use angles" int he light_env itself and this site
http://developer.valvesoftware.com/wiki/Sky_List It has proper light angles and such for the skybox, not sure if you were into making ur own angle or no tho, just thought it would help.
<333
However above all else...
No...
Lot less number plz...
LOTS
For lol's i put that fog brush into a 128X128 map and got 19fps...