Get a new flex pipe from zzp to replace the one that comes on them.

Make sure you have copper rtv, and use lots of it.

The headers replace your down pipe and the pipe is 3" which won't bolt directly to your factory cat.

If you want, get a 3" high flow cat like I did from zzp also. Then use the flange that connects the cat to the res as a reducer and you're all set!