Replacing cats

[l8agin]

My 2016 Explorer is at the dealership and they're saying all my cats are bad.  I think the performance tune may have contributed, but that's another story.  They said my vehicle has 3 cats and prices are quite high.  In looking for alternatives, 2 other dealers I spoke with say my vehicle only has 2 cat converters.  I'm thinking the third is the resonator?

Besides for my personal clarification, the reason I'm asking is because I'm thinking of the with the PPE catted downpipes instead of the oem cats in the front.  But those look like they only include the front cats.  Will I need the 3rd cat/resonator?  I'm in Maryland and want to pass emissions.  Any thoughts or suggestions are appreciated.

[SHOdded]

only need to replace the usual 2.