"Service Engine Soon" light after muffler delete
 

fixed

I don't believe there is anything causal here, just coincidence. I replaced my center muffler and deleted the rear on my 05 545 and had no issues. Have the code read at an auto part store and go from there. Good luck

Muffler delete itself won't make your light go off.

What MAY have happened however is during the process of the cutting/welding/vibration from the newly added resonance may have shaken something else loose up front. Perhaps there is a leak near the exhaust manifold or cat converter.