Can get 2 380x nitro 4GB for 350(new).Should I?

I have already 1 sapphire 380 nitro 4GB in my computer and it's mining at 20MH/s on nicehash, giving me pretty decent income when I'm not using my computer.

Right now I found some totally new 380x (and some other 380) in the range of 150-200€, and I was thinking of getting the cheaper ones to make a 3-4 mining rig with 380, is there any difference in mining from 380 to 380x¿? can I get them both on a mining rig?

What would you do? GPU are absolutely new, being sold at lower price by a trustworthy web because they have deficiency on the boxes they come in and some of them lack the manuals, as for the GPU, totally new and 2 year warranty.