monitors to sub tuning, using high pass output on subwoofer back to amp?

I just got a SVS sb1000 powered subwoofer, thanks to some advice on this forum.  It is being used with a NAD c356bee integrated amp, marantz sa-8005 cd player, and dynaudio x-14 monitor/bookshelfs. 

Before the amp, I felt the sound of the system was great.  But was missing to much lower end to where on certain songs I felt like it was not complete.  The sub has really made the sound feel more full, and sounds great, or will after I get done dialing it in.  right now I have it crossed over at 80hz, volume about half, have not played with position or phase yet. 

I like the volume loud and about 50% on my nad's volume knob is where I like it, at that volume the Dynaudio's mids start to sound like they are doing to much, maybe starting to distort at the lower frequencies, so I keep the volume at around 40% to keep this from happening. 

Now that I have this sub it has a high pass output that is fixed at 80hz,  So I am thinking about running my pre-out to the sub, then the subs high pass output to the amp input.  Everything I have read says that this will make my monitors sound cleaner since they wont have to attemp to drive the lower frequencies.  My question is the sub will be anywhere up to 12' away from the system, so that is 12' to the sub, routing throught the svs crossover of unknown quality, then 12' back to the amp.  Will I be degrading the sound quality to the point that I will notice it.  Or will the benifits outweigh any minor degradation.  I currently use kimber kable pbj rca cables and would probably go with something of similay pricepoint. 

And in generel what are the feelings of using a high pass output from the sub
If you don't high pass your small Dynaudios, you're missing out on the benefit of a sub.  Try it out with your favorite cables, and you'll see.  
The biggest problem is really noise. 12' is starting to get long for RCA cables, and potentially very pricey too!

If you could use an active crossover instead, such as from Bryston,  which you could put on top of your receiver you would be in better shape.
Does the SVS have speaker level inputs and associated high pass output?

Can you move your electronics closer to the sub?
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The best way to high pass your main speakers is to install a capacitor of the correct value to the input jacks on your power amp. However, that requires your integrated to have pre out and power in jacks. The value of the capacitor will determine the frequency of the high pass filter (the formula is available on the 'net), and will be a shallow 1st order-6dB/octave.