Synergistic BLUE receptacle question

Hey guys. During the Quarantine  I decided to finally start setting up my home studio in my garage. I just ran 2 dedicated ac lines with 10-3 romex. My question and concern has to do with the receptacle boxes. I don't know if I should use plastic or metal to get the best results? The 2 receptacles l'm using are Synergistic BLUE and PS audio. I've read mixed reviews about the whole IG thing. I have the extra wire with the 10-3 so I was wondering how I should wire these to get the best results? Plastic or metal box? Any advice is appreciated. Thanks
Why two lines? Mikey at 15:50
Oh well. Plastic or metal is the least of the least of the things that matter. If you care the only way to know is buy both try them and see. I'd go with metal only because its a little stronger, hence dynamic, material. But really, you are splitting hairs. And this from a guy with more split hairs than Vidal Sassoon.