[Japresto91]

Hello all, fairly new to the forums and just wanted to reach out for some thoughts on an issue I am having. I just recently received and installed AA headers to my N51 128i. Before this install though I had already done secondary cats and muffler deletes. I was not aware with these headers that the sound difference would be as drastic as it is as I have never done this before. I am looking for a solution and if I cannot find one plan on re installing the stock headers as it was perfect before. I also have an incredible idle surge about 400-500 rpm with these new headers and have reset throttle adaptations just not driven very far. Sorry for my broken english, any help would be greatly appreciated.

P.S I do not have access to the stock muffler as the shop discarded it and I had forgotten to take it when I had the job performed.