I'm not starting a cable debate, just saying what I have found.
I have used a £30+ 5m QED sub cable for the last 3 years I forget the specific model number with no problems I personally have always used QED cables throughout my system as the build quality is excellent.
However, I recently added another sub as an experiment and got hold of a cheapie 4.6m Belkin Pure AV silver series subwoofer lead off an ebay trade seller for £7.50 delivered (bargain!) and it works a treat the build quality is also excellent and soundwise I can tell no difference between the two leads on blind testing which was a real suprise to me.