To the OP:
http://www.youtube.com/watch?v=QRmVpP9EXgM
This is from a few days ago. Same engine, different Nova. You can hear the X-pipe sound a little better than just off idle. With the Magnaflows, it's REALLY loud inside the car once you step on it, and relatively quiet at idle. I love that, but some people don't. The flow/scavenging gains from an x over an h pipe are night and day. If you can spring for it, get one, you won't be disappointed.
EDIT: It's a crappy video camera (aka, my phone), but you can hear it SOME when the throttle is opened, when the camera is inside the car.