Fantastic review!
I must get it. I have no room. Has that stopped you before? I already have the big chap. See last question.
That's a tricky question. I've been in a phase the last couple years where, if I feel I wouldn't miss one of my collectibles if I sold it, I sell it. So space is not quite at a premium for me. This also mean I may not be the best person to ask since I tend to sell anything that feels redundant or simply "okay." And my feelings for most of my stuff have changed over the years.
With that in mind, if I feel strongly enough about a new piece, I'd find a way to make room (whether it means selling something older or carving out a new spot).