Wow, it seems that you did quite a good job soundproofing the room. I have spent many hours researching the subject (mainly reading what was available on the net 8 years ago), but never learned about the BSW products.
1.
Do they have a special line of products dedicated to rooms soundproofing ? Their web page only shows their pro products, for silencing entire houses, railway track beds etc.
2.
Do you have more images showing in greater detail how those aluminium studs are attached to the sidewalls ?
1) BSW produces the isolator foam. Then you need to use this foam in different application. I had a local Taiwanese company design for me what I wanted. It is not very difficult, you just need to get the spec curves of the BSW product and deduct from your specific load what is going to be natural frequency of the isolator and therefore the vibration insulation...
You can also use other products from other companies. Vibratec proposes for example an equivalent product (iso-T) in term of function, where the vibration isolators are already mounted on wooden battens (see pic below), you just screw your plasterboard sheets on these battens.
Vibratec has a full range of products focused on this type of application... I didn't chose them because I didn't want to import from Europe, so I designed local solutions.
vibratec range
2) here the design I used. As you can see, the metal rail supporting the walls of the box in box are fixed in a sandwich of BSW isolator. That means hat the junction with outside wall is done only through the isolator.
The logic is the same for the floor and the ceiling. This is working very well: I can listen to music as loud as I want at any time. The theory is easy. Devil is in the detail of execution.... one single screw which is too long and create a bridge between outside and inside wall, and you can lose 20dB of insulation.... That means you need to think through everything: how do you deal with holes for passing cables, how you will mount electrical plugs, how you deal with sound escape from air conditioning... and in my case even how you want the structure to move in case of earthquake (in taipei, the earth can shake quite a bit....).