hawaii 5-0:
DynoMax makes a good high-flow catalytic converter system for the 5.0.
The Super-Turbo cat-back is very good quality. I've had a set on my LX for theree years with no problems. The fit was excellent, much better than average with no cutting or extra bending to 'make it fit'.
I recommend DynoMax products based on my experience with them.
You can check out their web site at:
www.dynomax.com