Diffrent LCS Mac G5

Hi to you all. I just bought a well-loved G5 2,5 Quad and now i'm wating for delivering. I've read several posts about G5's coolant leaks but I'd like to know little more about these two different types:

http://www.mac-resource.com/parts/661-3729.gif

Can someone tell me if the dual pump model is the more safe and reliable, or the one is worth the other? According to the posts and forums I've found on the net, it seems the single pump one is
the most affected by coolant leaks.
Thank you
Rob