P0420/ bad cat fix question ..High Performance / stock sound?
I have the common P0420 code and have read through tons of information about the cats being historically bad on Nissan Trucks. I am contemplating the recommended header swap (undecided which type) in lieu of the stock manifolds with cats embedded to eliminate the cats damaging the engine and upgrading from the poorly designed manifolds that crack. I know the uprev tuning is recommended with the header swap and some type of mod (emulator or move the after-cats o2s to secondary cats in B pipe) to stop the CEL. I however do not want the truck to be loud. I am looking for a modification plan that fixes the CEL permanently, eliminates the possibility of damage to the engine because of poor design and is not louder or much louder than stock. Of course I am ok with more power and torque, but those are not my primary concerns. I live in KY so there is no emissions testing required.
1st Option: I have considered just gutting the cats in my manifolds and getting the emulators and then reinstalling the manifolds and calling it a day... seems the least intrusive and closest to stock.. the cost would be primarily labor and is a permanent fix... although I am not sure if that would require retuning... the downside is the stock manifolds have weak points that crack, although mine seem to be fine.
2nd Option: If I do Long Tube headers only with emulators and the uprev tune... this gives me the permanent reliable manifold but are all the headers the same, I have seen mixed reviews on stillen, jba and doug thorseys... seems the thorseys are higher quality (and most expensive) from what I have reviewed and if everything else on the exhaust (b pipe and muffler) is stock would it be louder... could a resonator fix the increased noise level?
3rd Option: Is it possible to have the best of both worlds... increased power and quiet operation with headers, tune, high flow secondary or eliminated secondary cats with no CEL ?
Compatibility question: although my 2004 Armada is a Pathfinder/Armada are the manifolds the same? It has a 5.6L but some manifolds say they will only fit a 2005 forward Armada... is this just because in 2004 it had a unique pathfinder/armada naming convention or is there a difference in 2004 from the 2005-2006 models?