2014 Cascadia day cab Exhaust bellows flex pipe

Hello, I have a 2014 Cascadia day cab and I've been getting exhaust smell in my cabin and a whistle sound on idle and acceleration with the sound of an exhaust that has a hole in it and I peaked down and saw that the exhaust flexpipe between the one box and the turbo down pipe has split right down the middle and the webbing around it too.

The dealership sell it as a whole pipe with the flexpipe welded on but I can get just get the flex pipe alone online for half the price. Should I just get the hole pipe or just the flex pipe then weld it? I mean the labor would add up and I might as well just get the pipe I guess but I just wanted your opinion on what previous people have done to fix it.

Would it be causing the whistling noise too? Or is that an intake manifold sound. The sound looks like it's coming from the flex pipe but I was wondering if it makes that sound too. Does it lower fuel economy as well?

Here is the diagram the dealer sent me.

Thanks