I had some brackets made up and used some sheathed/sleeved screws to attach it to the case. Fans were drawing air through the rad and being expelled against the wall
Predominantly for temps, however those Xinruillian 120mm fans weren't too loud externally anyway. The Cooler Master Stacker 830 doors are largely made of mesh so it's not really the quietest case anyway if you're aiming for total silence.