99 Silverado 5.3 exhaust question

[caspear1978]

I just picked up a 99 silverado with the 5.3. The previous owner cut the stock cats out do to being clogged. Did a pretty butchered up job. He cut the exhaust out in hopes to running duals. I crawled under the truck today after work and noticed he did a pretty bad job at welding some short lengths of pipes on to the elbows coming from the manifolds. and run them to some new cats.so having new cats ive decided im just going to order a new intermediate pipe and a tail pipe with an after market muffler. im looking for a more quite sound to it. so with everything ordered the only issue i am having is with a y pipe, i have cats. how hard would it be to take a stock y pipe and just add my cats to it to run in the system, or would it be easier to order a new y pipe and just do it back to stock? What are your ideas and opinions on the matter?