I knew that this was coming! It is 8mm OD x 6MM ID tubing and yes it is a low flow system. Sorry, I do not like garden hose. It is all from Aqua Computer in Germany, except for the NB & SB coolers which are from MIPS in Germany. Please do not discount low flow systems and small tubing as their design allows for a very efficient setup. My temps are quite low and the system is very quiet. The software allows you to set your fan speeds based upon temps and it also allows for shutdown in the event your H20 level falls.
I just replaced my E6600 with a QX6700 so I do not have an accurate idea of how the temps will be with the QX. However, my temps with the E6600 never exceeded 46~47C with an OC of 3.7. Currently the QX is 33C at idle....more to come.