Hello, I'm Albert Cartwright From New jersey. I have a few questions.

1. I have a 2002 dodge Dakota with a 4.7l engine and its rear-wheel drive. now my truck was set up for California emissions. I have a y pipe that has 2 cats, 4 o2 sensors, and one other cat or something before the muffler. I'm looking to replace all the exhaust. I have been looking for a few weeks for the Y pipe but can't seem to find a reasonably priced one . is there a second y pip not made for California on all the other dodges that I can use one of these instead? any help will be helpful

also headers vs manifolds cons and pros? is it worth putting headers?
I also want dual exhaust?
please feel free to text me email me albertcartwright@gmail.com in subject put 02 Dodge 4.7L
Thanks in advance.