[DCSpecial]

Longtube headers and high flow cats:

Of course if your state requires you to pass emissions there may be issues with Longtube headers and high flow cats.

 

[DCSpecial]

Same with the Magnaflow X-pipe, it throws P0420 & P0430 CEL for catalytic inefficiency.

With Longtubes you probably could add a P0133 and P0153 for slow response of sensor 1 on each bank
Either from the O2 extensions or from sensor 1 being further away from the head are what I have heard speculated.