I *think* we have a bad cat on one of our work trucks. It's an 03 2500 HD, 6.0 I have that sound the cats make when they start to fall apart, but no check engine light. I called ahead to the shop we take our stuff to, to get pricing just so I'm ready. They said $3500+ for the full setup OEM.

Are high flow cats a good idea in this scenario?

I haven't been under the truck, how much different is it than my 5.3 1500? That pricing seems excessive.

any recommendations?

 

depending on where you live and what it's used for . . . cut them off and put a pipe in it's place

Cats off of others will work . . . the come up on here for sale often

 

Wow does that price come with Vaseline and a hand release ?? That's absolutely insane, they should be arrested for trying to rob you .

Call some salvage yards for a replacement "Y" pipe , should be about 2-300$ or so .
Plus you can scrap those cats you have for about 60$ a piece.

Btw I deleted the cats with straight pipe on my 04 van , runs great and it was free , well actually I made money scrapping the cats lol .