i have a 91 DA and i have a 4-2-1 header stainless steel header on it. recently when i was changing my oil i noticed i have a fairly large dent in second piece. i don't know when it happened and i haven't really noticed a difference but is it just me? should i replace it? is it hurting my performance?

 

most of the time when u get a dent, it affects the flow thus affecting the performece. your best bet is to jsut bring it to a muffler shop and tell them to chop of the dented area and reweld another pipe in place of it.