Which case should I get? Quality wise and design

That motherboard supports " DDR3 3200(OC)/3100(OC)/3000(OC)/2933(OC)/2800(OC)/2666(OC)/2600(OC)/2500(OC)/2400(OC)/2200(OC)/2133(OC)/2000(OC)/1866(OC)/1800(OC)/1600/1333". So your DDR3 RAM 1866 is fine, but you will have to set it to 1866 XMP in the BIOS.