Hi,
I just changed my exhaust line for an apex'i ws2 and it begins at the end of my stock catalytic.
Now, i want to change my stock headers and catalytic!!!
For the headers, i know that i'm going to buy a dc sports, but should i buy an 4-2-1 or 4-1???
And to replace my catalytic, should I put a test pipe or a hi flow, is there any difference???
If you have a headers and catalytic setup to propose me, it would be nice!!!

I NEED HELP

Thanks to every one!!!