Need more pictures!
From what I see, looks good & healthy. Looks like a little too much stretch. When you have a small grow box (like me), you will benefit from tight nodes. Can you move the lights down? plants up? You can get as close as 1" with CFLs.
It is possible to have an HID lamp in a small grow box, but it does take work to manage temperatures. I do have a 400W HPS in my 2x3x4' tall grow box. I can keep my temps at 81F with an a/c reflector and some circulation fans. I am working on my intake air & may be able to drop another couple of degrees.