I had already replaced the factory Y-pipe with the AFe Y-pipe before I had the SC installed. I had no CEL or surging. It wasn't until I installed the ripp36_2.2drg that I got the CEL. I did not mention the Y-pipe to Ripp when I requested the ripp36_2.2drg tune. I had forgotten about it. This time around however, I did mention it to them. Just waiting on the tune now.