Hello, I will buy some RIG component but i need some advice to build RIG.

So i will use these components,

Amd Radeon R9 280X (x4) -- Most of ppl using this card.
Intel Pentium G3258 Socket 1150 3.2GHz
ASUS H97-PRO Intel H97 Socket 1140 DDR3 1600 Mhz (PCI-E x1 Slot x2) (PCI-E x16 Slot   x2) -- So i can use 4 GPU Unit
FPS AURUM PT 80PLUS PLATINIUM 1000W
GSKILL 8 GB (2x4GB) DDR3 1600MHz 1.5v Dual Kit RAM

What is your opinion?
Do i have to buy ATX Tower? Or make RIG? Does any1 have blueprints for RIG I think i can make with steel.
And the main question is HASH power? How can i calculate be4 buy ?
And i assume i can use these RIG for all coins. Does hash power change based on what we mined ? For example 4.5Mh for LTC, 5 Mh for DOGE?
Thanks