Car details: 2016 Dodge Dart SXT 2.4L, approx 60k miles

Changes: Injen CAI, Magnaflow Exhaust Manifold and CAT, Magna Flow Exhaust.

Codes: P2096, P0420, P219A

Hello good people and Scotty! Giving background then question; I have a 2016 Dodge Dart SXT 2.4L and I have been having troubles with the codes listed above. I have installed the above modifications to my vehicle. What I have done is: cleaned the MAP sensor (twice), replaced the spark plugs, checked for oil leaks, checked and cleaned the air sensors, cleaned the temp sensor. I am still getting the current code of P2096 and I also noticed oil on my MAP sensor. I checked my spark plugs and they don't seem to have oil on them, maybe a little. Unsure if I have a leaking valve cover gasket. I am sure it is not the CAT for I have taken it out and tested it, maybe it is the sensors not understanding the new flow amount and the computer can't compensate.

My questing is from what you read above, what do you think my issue is? I know it is a dodge/Chrysler/fiat car but I still want it to last a little longer and get some use out of it. I look forward to your responses!

-Luke