Subwoofer placement questions

In my current system, I have Spica TC-60's sitting on top of Audio Concept Sub one passive subwoofers. When listening, I pull the speakers well out into the room. I know this set up is not ideal for either the Spica's or the subs. If I purchase stands to put the Spica's on, I would need to move the subs out of the way to appease the wife's decorating. One sub would end up next to the computer desk on the long side of the wall. The other sub would end up in the corner next to the couch used when listening. In this set up, I will need approximately twice as long of speaker cable (25' vs 12') for the subs compared with the Spica's. I would expect more bass by having corner and wall support for the subs. I would expect better imaging and soundstaging from the Spica's by having them isolated from the subs. However, won't the difference in speaker cable length cause timing problems ruining the systems "prat"? Musical preference is varied from 70's rock/pop to country to female vocals and jazz and blues.

For info my system is:
Music Hall MMF-5 turntable
Music Hall CD25 cd player
Kenwood KT8005 tuner
C-J PV10A preamp
Musical Fidelity A3cr amp to Spica's
Carver TFM15 amp to subs
Homegrown audio super silver/silver lace ic's
audioquest Crystal bi wire spker cable to Spica's
Audioquest type 6 cable to subs.

Any suggestions are appreciated.