Since I have another autox on saturday I had Cam help me out. He welded in some new (and only slightly) larger mufflers...
The car is quieter now, but not a whole lot. There's definitely less raspy-ness to it, more muted, not really much change in tone. The old mufflers were definitely starting to degrade. If you pick one up you can hear lots of little bits bouncing around inside it.