2000 silverado 2500 6l vortec needs new cats and exhaust.

[Wcoastgrind]

Hey, I'm new to this site so i just want to say thanks for having me here.

 

I just bought this truck recently and it has developed a terrible rattle coming from the right cat and possibly muffler. I've decided to replace most, if not the whole system. I've been looking at the walker exhaust system from rock auto, and I have found two options the 3"in/out muffler or 2.5in2.75out. My truck currently has the 2.5 inch option which is stock.

 

http://catalog.walkerexhaust.com/catalog/resultsDiagramDisplay.do?diagramNumber=13_03690&catalogCode=walkerexhaustasset&locale=en&loadStatus=ACTIVE

 

http://catalog.walkerexhaust.com/catalog/resultsDiagramDisplay.do?diagramNumber=13_03691&catalogCode=walkerexhaustasset&locale=en&loadStatus=ACTIVE

 

the front pipe stays the same in both options but the diameter of everything else changes. Any benefit from going with larger pipes will i gain or loose anything? thank you, Josh