Hello all,
I have a 04 R53 I installed a reduction pulley, cold air intake, exhaust, 1 step colder spark plugs, & bigger 380 CC fuel injectors. I'm thinking about getting headers and deleting the cat. I know if I delete the cat my check engine light will be on. When I get the flash tune will that take off the check engine light? Or was that a bunch of bull someone was feeding me?

 

Nope, delete the Cat and it will always be on, unless you can possibly trick the O2 sensors somehow, there needs to be a specific variation between the Front and Rear sensor that the Cat gives, some people have gotten lucky with spacers, might work, might not.

 

I am lucky with the spacer, I ordered mine from outmotoring. it has a small cat in it. I am throwing no codes related to the cat, and I was code free for 3 months until I blew apart my mid pipe gasket. now I have a lean condition