[breathe_nitrox]

I'm looking for a heater core that I can mount side by side 120mm fans. My first question is given that I want 2 side by side 120mm fans, what should be the min length and width of my HC. Converting 120 x 240 mm gives me 4.75 x 9.5 in, but I'm assuming that a 120mm fan really is 120 x 120 (4.75 x 4.75). I don't have the fans yet. I found a couple of HC on www.heatercore4u.com, the 2-205 (10.75 x 6.125 x 2.5) and the 2-617 (9.875 x 6.125 x 2). There both about $50.00, and have 3/4 inlet and 5/8 outlets. The inlet and outlet on the 2-205 are both on top of the HC and are perpendicular to its face. On the 2-617 the inlet is on top and the outlet is on the bottom, both are parallel to the HC face. Does this difference in inlet outlet arrangement make any performance difference? Given that the 2-205 is slightly larger (and thicker), I'd assume that it cools better, but how much better? Do you think it would be noticeable? I should mention that I'm mounting the HC externally and will be using a 2gal fish tank as a res. Aesthetically I'm leaning more twords the 2-617, but I'd like to hear some input before I go ahead. I was planning on using a Swiftech dual rad, but it doesn't look like I can go with 1/2" ID tubing without a performance loss due to restriction. In addition to the 1/2" tubing, I'll be using an Eheim 1250. Sorry for the long post.