Ecto-1 theme ideas:
-white cab (use white vinyl to give that shine look)
-red t-moulding on the sides, Chrome around the CP.
-giant tilted GB logo across the sides
-tinted display glass
-chromed/polished coin door, marquee holders, hardware
-Chrome/polished bat tops, black push buttons with yellow plungers for p1. Yellow buttons with black plungers for P2
-Blue Coin door buttons
-some sort of blue hazard lights on or above the marquee.
-blue under and back glow.
-yellow serial number plate
Alternatively you could do Chrome buttons with translucent blue plungers and light them.