Ok, i made back panel now for the radiator and hard drive area i made a sandwitch of two pieces of aluminum sheets folded them in the way i needed them and stuffed them with thermal isolation that will help muffle the sound as well and made entire thing really sturdy at no weight cost
As for hard drive mount, i will make a sort of floating floor for almost complete vibration reduction, it will be two sheets of aluminum, bottom one mounted, than spounge in between 10mm thick and another aluminum sheet on top of it, connected to the bottom with rubber going all around it