Speaker Cable Length

I, too, have to run 15 foot cables. No issues.

Nope it should be fine. You are very unlikely to hear any difference.  I use Transparent Ultra Gen6 speaker cables... I think mine are two meters, but I have used four meters before. These are great cables.  It’s not until you get up to 25 or 30 feet that there could be a noticeable difference 

Here is what Paul says:

https://www.youtube.com/watch?v=6e8UTpBOStA

I’ve been doing custom installation for 25 years... I’ve wired built in speakers with 16 gauge 4 conductor basic in wall speaker wire that is 300 to 500 feet of cable running through walls and conduits, and next to electrical main power wires...

Works fine, sounds great, no loss of bass... 15 feet of high end speaker wire is nothing, immeasurable and inaudible 

@woots you should not hear any degradation in sound quality with longer speaker cables. But why not bring the center channel out into the room some more and leave the burmester amp in the middle between speakers but behind the center channel?