My first Ethereum mining rig. What do you think about my hardware?

Hey guys,
what do you think about my setup?

3 x Radeon R9 295X2 GPU (2x 4GB GDDR, 150Mh)
1x MSI Mainboard Intel Z170A Gaming Pro Carbon 64GB ATX SATAIII | 7A12-003R (7 Slots)
6x USB 3.0 PCI-E 1X To 16X Extender Riser Card Adapter Power Cable Mining AC579
1x HyperX FURY HX421C14FB/8 Arbeitsspeicher (8GB) 2133MHz DDR4
1x Intel BX80662G4400 Prozessor
1x SanDisk SSD PLUS 120GB Sata III 2,5 Zoll Interne SSD, bis zu 530 MB/Sek v
1x EVGA 120-G2-1600-X3 - SuperNOVA 1600w (or 2x 750?) What do you think?
1x Lenovo ThinkVision L191 LCD-Display TFT
1x TP-Link HS110(EU)

+ 4x R9 295X2 GPU if I have the money
+ 1x EVGA 1600W or 2x EVGA 750W?