Go with what blue recommends or go with Thermochill PA 120.3 rad (known to be teh best performing rad on teh market - at least that is the GENERAL consensus). Now some of my Next Gen bros say the Koolance ones are better . . .can't say that and then a Danger Den bud likes HWLABS stuff over all others so experts can disagree. But MOST people out in the intraweb think Thermochill is the way to go. Either way you will probably only see a MINOR difference in temps either way (maybe 1c). My suggestion is to go ONE vendor and style meaning if you go Koolance then go ALL Koolance. Their stuff is made to work with their stuff. Now you can mix Danger Den and Swiftech and EK . . .All of their stuff is great. I would say go with a 3/8" system. DO NOT go 1/4". The flow change from 1/2" or 3/8" is minimal from what I have heard but 1/4" is supposed to have a greater delta.
What you might consider to use use the CooliT as a waterchiller that you add to a new setup of beefier cooling equipment. Set up whatever new equipment you choose (if you want Koolance the bros here will help otherwise you should go to
Danger Den Community Website - Home) and add an additional block. Connect that block to your coolit cpu head. it will help chill the water and improve the effeciency of your loop. If you are going to get another loop tho I REALLY suggest you just have Travis make you a phase change unit as the additional couple hundred bucks will TOTALLY bring u to the next level. I am gonna pick up a QX6850 which I should be able to get <<hopes>> 5 ghz in Hellmouth . . .that is if Travis is talking to me anymore . . .hint. . .return phone calls. . .