[BOSE 901s or Klipsch Chorus II NEED ADVICE]

Dick, do you mean what the II designation is? The original Chorus (guys,correct me if I'm wrong) had a tuned port, the Chorus II's switched to a passive radiator design, thus you have the Chorus II. They may have made other small changes but, I'm not quite sure what they are.

I'm looking for a pair of Forte' II's, I want to use one for my center channel.

The Quartet, Forte' II and Chorus II are all awesome speakers.

[BOSE 901s or Klipsch Chorus II NEED ADVICE]

I have a pair of Chorus II's an absolutely love the sound. If you like the sound of Klipsch why not go with a smaller version of a Klipsch speaker? Bose? hmmm, I don't think that would be upgrading