Hi,
I just bought a used 2009 Cayenne GTS. After a week of ownership I installed Fabspeed cat bypass pipes and got the Rattle. It's been 4 months, many hours of troubleshooting, and Fabspeed acts like I'm the only one who has ever mentioned the problem. Did you resolve the rattle issue? How? Do you know what the cause of the rattle is?
360 490 7741 or
Pete.spyder.rs@gmail.com