Speaker load may be a problem for the amp which could adversely affect it's performance. Read the fine print to make sure your amp can handle the speaker load you plan on giving it.
A/B speaker switching - advantage?
What is the advantage of having A/B speaker terminals, besides being able to swap between two sets of speakers (maybe for sound quality checks)? Is it beneficial to have two sets of speakers connected to the terminals and have both A and B speakers on at the same time? I know you can connect a powered sub high-level inputs to the B terminals, but what if I expanded my current bookshel/powered sub combo with floor standers, and had the 4 speakers on the terminals and the sub connected to the pre-outs, would this have a negative effect on imaging/soundstaging?