Can 5th gen mufflers give us any HP gains? And if so, are they for sale?

 

I'm not sure if they do. I have one, but I installed the B-pipe and muffler together. I had a noticable gain, but I don't know if its all the b-pipe, muffler or both. I think when you open the exhaust system with the Y-pipe and B-pipe, you need backpressure on the low end. That's why I decided to try it. I guess the only way for me to know the gains is to just bolt my 4th gen muffler back on.