I already have a cat back and aftermarket cat on my civic now, both of which where specific for 96-98 civic hatch(so it said). I had to purchase a cat to reach the headers. Everything bolts up true right now.It also had a o2 sensor on the cat which i plugged, no problems there, I'm convinced that if I buy Y8/9 headers everything will line up right. I heard that d16y7 headers have two o2 sensors, and d16y8-9 only one, is that true? anyways,Thanks for your fast reply silverY2kcivic, you've been a big help.