Hello Z4 fam. I have a 2007 Z4 3.0i and bought a used sound generator online and installed it. Now when cold starting it surges on idle for the first 10ish seconds and sometimes seems like its not running the best. Is there a different assemble for the N52 and M54 engines. Maybe I bought the wrong version?!?!?! Also I installed a 3 stage intake a couple of years ago and had it tuned for that. Do I have to tune the car for the sound generator also since mine didn't come stock with one? Thanks for any help...