shitty kitty

One of my cats customarily craps on the floor. Everyone who knows me well knows about the famous Shadow, whose picture and name are on this very site. I think this happens partly because of something in her past. Perhaps she grew up feral as a kitten or partly so. Her wild behavior when she first arrived her two and a half years ago suggests as much. But whatever tactics I have employed, although she has become a loving and charming little cat, the litter box behavior persists. She urinates in the box, never outside of it, and is scrupulous about covering it up. However, most of the time, she poops outside the box. I have tried many different kinds of litter, as well as being quite careful to clean up poops as soon as possible and to spray with something that will take away all smell of waste, but she apparently still detects it somehow. Thinking that perhaps she'd use the box if I moved the big box to the bathroom and left the small one in Jeremy's hall, I switched them, but so far, no cigar.
Shadow has also become very aggressive towards Whistler, my obese and withdrawn Snoeshoe cat. She yanks out great hunks of hair and chases him around.
I am pretty sure both cats are really bored, though I cannot find it in me to entertain them day and night. I enjoy their company, but I don't want to wave things in front of them all the time.
I have to clean up the living room so there is someplace for a cat tree that will allow them to look out of the window. Now that the aquarium is gone (or at least empty), I can open the shutters during the day and put a tree by the window. I have been checking out cat tree prices on Ebay, and have found some with free shipping. It would cost less than getting one at a yard sale, and I am not so hot at finding those anyhow.
Let's hope that does something to alter her behavior.