SO i ran by autozone today to run a diagnostic to see why my car has been throwing a CEL every since I got my header installed. I have the angled defouler present so in my head I knew one of the 02 sensors was bad. I figured it was the primary 02 sensor because those ******* conartist at Mahdavi Motorsports replaced my secondary o2 sensor at the time of install. Anyways diagnostic comes back and says that both o2 sensors are now bad? WTF!!! i had no problem until they installed my headers... my mod list in order is 1)Exhaust 2)CAI 3)Header and a CEL 4)Reflash Still a CELL! So i know it was those bastards @ Mahdavi. I called to find replacements and it is nearly $200 dollars for replacements all because some **** didnt know how to do it properly? im looking for advice here what should i do guys?!?!