No flaming pls!

[JoeBar]

I want to tell u my wc story. I know that many of u don't like them (especially maxx ) but i've used only theramlatke's wc kits. My first one was a bigwater se (an upgrade from a big typhoon) and it was done mainly for educational reasons. After 2 weeks bigwater 745 came here and i was tempted...
So i went a bought it and all i can say is that i'm imressed! My 920 couldn't go over 4.1ghz with my previous setup and now i can reach 4.5ghz (with 1.55v) and my temps even @ these settings and the rad fans spinning @ 1450rpm never get above 50'C in a closed case with 22'C room temp. For its money (150$) i believe it's one very good setup!
My question what temp difference will i get from a custom setup and what should it be? Is it a valiable option to upgrade some parts of it like maybe getting a black ice triple external rad an a better waterblock or shall i ditch it for an all new setup.?
Note that i would like to stick to 3/8 tubbing unless u think otherwise.

[KaptCrunch]

if you want 3/8 tubing, corsair cool uses that size.
for others will get a little cooler but alot less noise an most custom are 1/2 tubing

[JoeBar]

Thanks for your answer.