That and its not the top shelf water block from Swiftech, but the XT is the same price as the whole Eco system
I have no issue with kits, never have, they have their places. Those who go the DIY route are also wanting to do video cards and chipsets as well. I get email all the time from people asking how to splice into the loops to add stuff. When the kits can be spliced into, or added, we can then see where the cost comes in.
As for the tubing size... its always better to have a bigger tube