MathiasVO053

With EK's kits, any of their X3 reservoirs should work fine. The size of the reservoir doesn't impact performance or pump requirements at all, it is pretty much entirely an aesthetic choice. They're mostly plastic besides the fittings, but there's no copper in them, no need to worry about mixing metals. 
 
You may need to purchase more coolant as obviously a bigger reservoir will take more coolant to fill.

We'll have separate Aluminum components available later this year.

Your welcome! Just remember, the thing that matters most is how you feel about your build, not what other people think is cool. Just do your best, and it should turn out well. 

lel, thanks. i'm a derp

No problem. There's so many buttons on sites now, lots of us tone them out, so you need someone else to look at it to see it. 

As far as expandability goes, you need to make sure you're looking for aluminum parts and right now EK isn't selling any outside those kits. On another thread, though, someone did link to Koolance, who has some aluminum parts.
 
Look around the forums a little bit and you'll get some more answers. Everyone is asking questions about those kits since JayzTwoCents posted that video.

yeah, ik. that's why i'm wondering where to buy things like aluminum radiators, fittings ETC(preferably in the EU)
also, i really doubt that a 240mm radiator can handle an overclocked GPU & CPU, soo. yeah

Here's my potato PC slapped into my new case for a quick pic:
I think it looks good. Pair it with some RGB fans and a custom loop, and it'll look even better. If I added more RGB strips, RGB RAM, etc, it might start drowning out my components. I'm also planning on getting a Gigabyte Gaming K7, which has nice RGB around the RAM and GPU, so it'll highlight me components instead of drowning them out. 
 
That's for a black/grey case. If you have a white one, you have to be careful to not overdo it, as white will distribute the light better, and you get the drowning out the components problem again. It all comes down to what you want people to look at. If you want people to see your mobo, CPU block and GPU, then try and highlight those, or just provide some nice ambient light so you can see them better. If you want everything to be RGBified, then make that the theme of your build. 

ahh, yeah. i see. thanks