Also another trick for them not being able to read the cat and its perfectly legal is to add a heat shield.
California smog law states you have to check for a cat, but if theres a heat shield, you are not required to take it off.
Im located in Oxnard, CA 93033
I have parts off a 520 but can fit the 521
Bed-one side is good but the other has a dent by the gas door 70 obo
Cab-has rust in floor boards and roof is dented 70 obo
ill look into the rest of the things i have tomorrow and post
you can also ask and ill reply if i have it or not