Meaning, when you purchase a new one from the muffler shop, or wherever, does it come in one complete piece? Is there any welding involved? i have an aftermarket exhaust on my stock tailpipe and i've never had to replace that yet. now the tailpipe is getting rusted out. i'm thinking of just putting on a stock muffler/tailpipe if it's easy enough for me to do at home. is there welding involved? how does the pipe attach to the catalytic convertor? thanks for your help....