I didn’t do this but got it from someone 

we have seen all sorts of custom clear side mod but technically most are laborious and mutilating to oem part.

the three outer shell casings of case were removed exposing mounting screw holes

front and back bezel are fastened together using two screws on top and two at bottom 

I realized how heavy R2 case is even with a light build. I think psu added to weight.