You may want to consider the Quad 989's. They cost less, you will still get the Quad sound and more bass with the two extra bass panels. Before you consider the other choices (all of which are excellent), consider trying to audition 989's in your current system.
If you rule out the 989's, then consider how wedded you are to your amp since you may have to change amps with many of the other speakers.
If you rule out the 989's, then consider how wedded you are to your amp since you may have to change amps with many of the other speakers.