Vandersteens and room acoustics

I own a pair of Vandersteen 2Ce sigs with an Anthem power amp and Rogue preamp, and VPI Scout.
The Vandys sound really good but from past auditioning sessions, I believe they can sound better. I'm not sure how I would accomplish that (outside of new equipment) and I'm wondering if there are room treatments that would help in this room.
My listening room is 8W X 13L X 7H, obviously a less than ideal setup. The Vandys and component rack are on one short wall with the centers of the speakers about 5 feet apart.
The backs of the speakers are a little over a foot out from the front wall.
The "out" sides of the speakers are about a foot from the side walls. The best listening position I've found is about 6 feet away. The floor is reasonably thick carpet over cement slab with padding, obviously. The walls are bare.
Are there treatments that you would recommend? I have seen some sorts of traps behind Vandys and other speakers in system pics here, and elsewhere. What change would that give me? What about acoustic (whatever) on the side walls? Thanks in advance for any help.