So i'm going to do a complete overhaul of my exhaust system. I got a nice little bonus at work so i figure why the hell not. But my Cat has been slowly going bad for a little bit and my gas mileage has gone to crap since there is very little airflow. I was hoping someone who has replaced the stock cat with a high flow could let me know if the have had any problems with the O2 sensor reading a rich exhaust flow (too much oxygen). I am also going to replace my muffler with a single chamber, dual out muffler. I am aware it will be loud as hell, which i don't mind, but it will also increase power and gas mileage. I'm also building a homemade air intake with a K&N filter. Any configuration ideas? Headers are going to be my christmas time project btw.

 

Cant comment on the cats but for the Air Intake, get a 60 degree pvc elbow, use a pvc pipe to get it to the hole in the fender and get you filter as close to the cold air as possible. Mine came with 2 MJ clamps and a pre-bent piece if pipe. Be sure to oil it as well!