u/wowimrich12

I’m not 100% sure what this is, I think it’s a flex pipe, but it’s rattling under my car as if it’s a cat? I want to replace it with a ISR test pipe for 240sx. The only reason I linked those two together was because I was told test pipe direct fits to stock cats. Am I moving in the right direction or should I just cut it and put a pipe from Home Depot or something there.