I had to change my 02 sensor and noticed my exhaust manifold was cracked. Makes sense that my car was a little louder (annoying). I was wondering if i bought headers what will happen to my after cat o2 sensor? How can i accomplish this?

 

I got the cheapy pacesetter header and it came with stock location provision for the o2 sensor

 

All aftermarket headers should come with a hole for the o2 senser

 

What year Civic do you have?

Edit: I checked a thread you made a little while ago and saw you said you have a 98 lx. In order to install a "Performance header", you would have to do this:

https://www.hondacivicforum.com/foru...ad.php?t=73237