Thought I would throw my recent experience in this thread. I bought a Perrin dp from my tuner and had them install and tune.
Problem is the dp was made for the 5mt...I have a 5eat.
The dp rubbed on the firewall and against my tranny pan.
The vibration noises it put into my cabin were terrible. At first I didn't know about the terrible fit and thought all the noise was normal for a catless dp. Thus several panicked posts I made here about how to quiet it down.
I now have an invidia that was made for the auto and it fits like a dream and is almost as quiet as stock.