What's the purpose of these things? Are they just eye candy or is there a HP gain over the stock torque tube/baffle setup?

Last week I removed my silencer ring just to hear the difference...I don't hear the turbo now any more than I did before.

 

I noticed a little bit better throttle response and definitely more turbo whistle.

 

It is a really heavy duty part. I was surprised how thick(6- Layers of reinforced webbing with a stainless steel wire wrap) and heavy the cool hose is. I got a red cool hose to match my red intercooler boots. I never removed the silencer ring but it does whistle pretty good without being too much on long trips with the camper in tow.