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.
kolledog
@hilde45

" there are some things that just aren't done; such as drinking Dom Perignon '53 above the temperature of 38 degrees Fahrenheit. That's as bad as listening to the Beatles without earmuffs”

Perhaps. . .perhaps not.  I remember reading about a guy Mike Lavigne on another blog, who supposedly was convinced his power cables made an auditory difference, but under controlled, blinded conditions, he couldn't tell the difference between his $10,000 power cables and the standard OEM power cables that come with components.  
Post removed 
Moving the equipment rack from between the speakers and leaving the amp there significantly improved the sound of my system. The advice from my dealer and long time audio comrade told me that to break between the preamp and amp was the one to make. Shortened speaker cables can really make an aditional improvement. I trust him and did that this time. For runs of 20 or 30 feet… single ended RCA are fine.

@steakster 

If you're interested, I think that the blind study with power cords was done in October 2007, and is on the AVS forum.  I'll see if I can post a link:

Observations of a controlled Cable Test | Page 2 | AVS Forum