I'm new to the forum and was looking to get some answers. I just bought a 2010 mustang GT. The car is 100% stock other than a muffler delete. I am now wanting to get a UPR O/R X-Pipe for it but I know it will throw a CEL and not pass inspection. I am trying to find out what people recommend or have had experience with, I was looking at either an o2 sensor spacer or a spark plug defouler. Now I know both do pretty much the same thing but I want to see what ppl have had the most success with. If worse comes to worse and try both and still have a CEL atleast I have a whole year before I have to get it inspected again and I could just throw the stock X-pipe on it and get it inspected again but it's just more of a hassell than anything. Thanks everyone and look forward to posting more !:headbang: