I am wondering if anyone who has replaced their front cat, replaced it with sometihng other than dealer part?

Cali->Fed conversion and eliminate it?

Did it go bad?

I have the PO420 code , which is the cat, i changed the o2 senors before the cat and after, went to dealer twice to have the ecu reflashed, the light just doesnt go away, keeps coming back about 1000 miles afer the dealer turned it off. So i am ithnking of either geting rid of it or finding a cheap imitation of it. I dont have a warranty left, was tihnking aobut maybe a y-pipe, instead of wasting money on a new cat.

Okay, that's the other cat, ie closest to the firewall, so a ypipe would replace that without the Cali-Fed conversion hassle. However, that wouldn't fix your CEL, so either way you need to move the rear 02-sensor behind the main cat.

Are you past your state emissions warranty? If not, have the dealer replace your stock ypipe.

So either way iam stuck with the sensor that detects a falty cat. If i wanted to upgrade to say a cattman y pipe, i wills till have that code popping up, how would i go by getting rid of it if i get aftermarket y pipe?

have u reflashed the ecu? there is a tsb for that code

Assuming the dealer actually did reflash, you don't know unless you've seen the before/after part numbers, then the cat is bad. If you remove the cat with the ypipe, it will still throw the code.

Only way to fix it IMO without getting a new stock ypipe/cat combo is by moving the rear 02-sensors behind the main cat.