Room rearrangement. Cable question

I'm thinking of moving my large box furniture rack from its current position between my speakers to a location along a sidewall. The idea is to minimize speaker reflections and refractions off the center-positioned rack.
This leaves me with two options:
1) Running longer speaker cables  (15-20 feet) from the amp's new location on the sidewall to the speakers, or
2) Leaving the amp on the floor between the speakers (and putting it on a low platform), then running long interconnects from the preamp to the amp and using short speaker cables.
My Pass Labs XA25 amp does not have balanced connections.
Thoughts? Feeling? Speculations?
Thanks.