So ive had these installed for about two months and ive notices when I'm cruising i hear a noise, kinda sounds like metal hitting metal, like a warble. I contacted corsa about it and they said it was the afm valves when they open and close. I don't know if anyone has had this issue. I mean i never had this issue with the stock exhaust. Why would replacing the x pipe and axle back do this if it doesn't even touch the afms