Anyone use 'mini-cat' O2 simulators?

My truck is a salvaged fresh water flood truck. (yes I bought it this way) I think I have some semi plugged up cats because my powerband really starts to dump off on the higher end. I have another prerunner I'm comparing the powerband to.

Aside from all the assumptions people are going to make about water damage.......

Has anyone used the O2 sims that are a mini-converter? Where did you order them from and how were the results? I live in a no smog area so cats are not an issue. Was considering gutting them if necessary.

Also, in case my muffler is plugged up too, can anyone suggest a muffler that isn't obnoxious? More stock like? I can buy an aftermarket muffler for less than most people want to sell a stock exhaust.
thanks

 

If the muffler is clogged I would change that first and then see how the cats act. I had a thrush from Advance on my V6 Ranger. Sounded normal.

 

Ok thanks. I still need to take it apart to visually inspect, but I have my suspicions.

 

What year is it, 2005+ V6 has 4 cats. Upstream 2 are built into the manifold/header, downstream 2 are bolt on.

Toyota quoted me $2000+ for 1 new upstream one. hopefully your lucky and it's just the muffler or downstream.

 

So I pulled off one of the secondary cats (the passenger side thats bolted in) and can't really see through it enough to tell if it's plugged. There's a little bit of a bend in the pipe where it goes to the engine so I'm not sure if I just can't see through it because of the bend....or because it's obstructed. I know you can normally see quite a bit of daylight through a normal standalone cat. Odds are slim I would ever take this truck to a smog state/area, but still hate gutting the cat without knowing for sure.

 

Put it back together and did a proper test drive (which i should have done before) and put it in a low gear and it rev'd easily into redline. Guess a lot of worry for nothing.