Upload & Sell: Off
What you have here is the perfect situation for creating a "ping-pong" composition where two objects of equal attraction oppose each other with a less interesting gap in the middle forcing the viewer's eye to jump between them like following the ball watching a ping-pong or tennis match. That works better with only one phone booth...
While the windows are tinted and the camera captured that accurately, eyes in person would adapt to the tint and not see it, so I normalized the color with the eye dropper tool.
I also agree this is a good candidate for a B&W conversion because the color content don't add anything and tends to distract...
The choice of the darker gray mat is to make the tone of the foreground figures contrast more. I made it wider on the sides to add back, symmetrically, the negative space lost in making the square crop.
As for C&C on the capture of them image, had you lowered the POV of the camera a bit more you would have been able to eliminate the tops of the cars seen outside in the foreground for a cleaner, less distracting background. Also shallower DOF to slightly blur the background would have more effectively isolated the foreground.