I got my 2010 Cayenne a little over 2 years ago. A common problem with these is the flex pipes connecting the cats rust out. One went bad soon after so I took it to a local custom exhaust shop and had them do both. I remember asking them if I could get the cats first and shoot them with high temp (1800ºF) Cerakote. They said not necessary, they are stainless steel. (of course only the mesh is)
2 years and 2 months later, both are gone. Very mild winters with no snow so no salt on the roads.
I'm bringing it back this Thursday to have them replace both again. I sent them pics and we talked about will this cost me anything. They were nice about it but non-committal which I understand.
Cost was $500+ each for the flex pipes and $450 to weld them in.
