I like to think of myself as reasonably tech savvy, but some of the stuff in this process goes straight over my head. Recently I bought the upgraded 15" rMBP, with hopes that the 750m would suit my gaming needs under Windows. Unfortunately, I just want more out of it now. =<30fps at low/medium settings for last years games isn't doing it for me, so I think I'm going to return this one for the base model 15" retina (I hear using an eGPU with the 750m needs some workaround each time you boot). Anyway, before someone tells me to just build a gaming PC, it's just not an option for me. Right then, down into the nitty gritty. I'm looking at the Sonnet Echo Express SEL (http://store1.sonnettech.com/product_info.php?products_id=498) along with something like a GTX 770. My issue is, I don't know what that chassis looks like when I open the box. Is there anything else I need to order? Power supply? Cables? Risers? Do I just order those two things and plug everything in? Perhaps my biggest issue is not understanding the whole PCIe 3.0 16 lane deal-y. From my understanding, Thunderbolt 2.0 is incapable of transferring data as quickly as a direct PCIe connection (somewhat obvious). But at the same time, until you get to a certain point, a GPU won't utilize all of the speed available to it via a PCIe connection, right? What I mean is, a lower end card probably wouldn't even transfer data at full PCIe 3.0 potential, whereas a GTX Titan Black might. The reason I'm asking about this is because I'd like to know where the "sweet spot" is before Thunderbolt starts to bottleneck a video cards performance. Should I get the 770? Will I get more out of it than a 760? I'm doing my best to understand how this whole process works, I'd really appreciate if someone could explain what I'm not getting as if I were a small child. The last thing I want is to order $700 worth of non-refundable gear and realize that in order to get everything working I'm going to need to start reconfiguring kernel-level stuff on my computer. Many thanks to whoever responds.