Does anyone know where I would go for step by step instructions to install headers myself,and also is it easy or difficult?

 

did my best to be as comprehensive as possible

linky

other than the egr stuff yours should be the same.

 

What did you do with your stock cats did you reinstall them?

 

I recommend installing your Cats back up. But what headers are you installing? Shorties or LT's? Unless you live in a state with no smog restriction or you dont mind swapping your cats in and out every two years for smog inspection. In my opinion I'd leave the Cats in for a daily driver.