CEL caused by headers?????

[mazdatree(3)]

Looking at a set of MSDS headers, but this is my issue ive got a 2010 2.0l non sky, and ive deleted the resonator, second cat, and ive got a MF straight through muffler now, so will i get a code if i put a header on it like the MSDS that deletes the first cat?

[G ~ MINI]

I have MSDS installed with Corksport cat back , i have a CEL and goes off and on. Was told by Martin at MSDS that a tune should eliminate the CEL. Doing a OV Tune soon.
Was told by Raymond at Gilman Auto Service (on Ellesmere in Scars) CEL goes on because there is not a significant change in the pre and post exhaust and CEL lights up thinking something is not working.
A quick fix is to move post O2 sensor away from the exhaust flow (by adding a washers or spacers so it does not screw in all the way) ...but may still set off CEL.

[G ~ MINI]

Check Vibrant website. they sell a Bung for O2 sensor.