heatercore vs double heatercore

Have any of you gone from a single heatercore, or a single fan rad, to a double heatercore? i'm looking to do this and was wondering if i would have a significant performance boost, right now i have a blackice extreme running along with a maze2, eheim 1250 and the old cylindrical danger den res. as of now i do not have a gpu block but i am pondering getting one in the near future, so should i hold off until i purchase a gpu block or will the temp gains be enough until then?

edit: i'm using 1/2id 3/4od tygon r-3603 tubing as well

Well, you'd be serverd well to get a better block too... I mean the Maze 2 is not a great performer. I went from one Dtek rad to 2, saw about a 4-5C improvement, so yes, more rad is usually better. If you went to say a white water or a 6002 or an RBX you would see about a 5-7C drop right there with just the block. A bigger rad and a new block gives you the potential of around a 10C drop or so.

I went from a Dtek TC-4 and a single chevette heatercore(push/pull setup) to a DD RBX and a fedco 2-342(with two fans on one side pulling) and my temperatures dropped about 6C. I can't guarantee you you'd get the exact same number difference of course but a bigger heatercore like the 2-342 and a better waterblock(compared to your maze 2) will definitely lower your temp. I'm definitely glad I switched, even if the TC-4/Chevette combo still isn't a bad combo.