<Edit by Admin>
I have been told that the check engine light will come on? I also was wondering how else i could get the turbo whistle a little louder out of the exhaust! It seems like i only get the engine noise out the exhaust and i want to hear the turbo scream!

Please check this thread:
https://www.dieseltruckresource.com/...d.php?t=173874

 

Don't really know about the cat. I cut mine off, but I have an 05. If you want your turbo to sound louder just take out the silencer ring. it's located inside the intake side of the turbo. It's basically just a snap ring of sort's. You can remove it with a small flat head screwdriver. Just becareful not to damage the impellar of the turbo. It will scream like an eighteen wheeler when your done.