@Crabid, thanks heaps mate, all noted!
You missed these two:
I've also heard there's flat tubing* which performs better, have you ever read about or tried it?
What make/model tubing IYE offers the best performance/resilience?
Larger rad. will be the very 1st upgrade in my next wave of tweaks.
Once my build's done, I'll be sure to PM you my completed beast
*obviously not entirely flat
But no, flat tubing wont perform better, even if it does, round tubing performs so well that there are essentially no improvements to be made on that part of the loop.
As for the best brand, I personally don't give a damn, tube is tube, it all performs the same.
Though as I said before, primochill is the tubing most people recommend.