I just installed the invidia test pipe with CEL fix also and just for security added a T1R oxygen sensor simulator/CEL Fix and everything appears to be just fine no CEL after a slow warm up and a full drive. I highly recommend the invidia setup.

 

I've had invidia test pipe with CEL fix fail to keep the light off. Still had to add a spacer on 00-05 cars.

I have no solid answer for 06-09 yet.

 

I found that the angle defoulers keep the cel from occuring. 2008 CR no issues. you can get the angle defoulers from club rsx.

 

I jst put a invidia on my 08 cr with anti-fouler from autzone and it was fine for like 50-100miles? The cel came on today

 

Your CEL came on because the CAT monitor finally completed, failed, and commanded the light on for P0420.

Did you use the angled sensor? I have not had a chance to try it for myself yet.

 

Also when you do the trick as mentioned. Make sure you only drill ONE of the foulers not both. That way the opening will not be very big.