I have 2011 Cayenne S and I am thinking about to change exhaust.
(ex. Agency Power Super Sport Muffler Exhaust )

Before I do this I just want to make sure about warrenty coverage.

I heard factory warrenty does not cover the modified car, so I called my delearship and ask about this. The service man told me that if I change the exhaust, the problem that caused my exhaust will not be cover from warrenty.

So my questions are..

1)what are the problems that might caused by exhaust?

2) Is it worth it?

3) Service guys told me other problems not caused by exhaust will be cover by warrenty, What if they change the word? Can I argue with it?

 

You're in the US - so the Magnusson-Moss Act applies - which basically says that a manufacturer can't invalidate a warranty for items that wouldn't have caused the problem being warrantied. That said - there is no enforcement for this act - it just allows you to take them to court with your money and try to get them to pay. They have lots of money and lawyers on staff - do you?

I have heard of manufacturers denying warranty coverage on engine problems of all types when things like intakes and exhausts are changed from stock.

You ask is it worth it? Can't answer that - how much is a louder exhaust worth to you? If it's so desireable that you're willing to pay for any engine repairs (even if not caused by the exhaust) - then you've made the decision.

Can they deny they ever said this? Do you have it in writing? Verbal agreements are notoriously non-enforceable.