Alright guys. I have done a bit of research from other BMW forums, and am going to attempt to put performance headers on my 330xi. I have found some SuperSprint reproduction headers from eurospec.net which come highly recommended (lots of owner-tested miles). I have one question. Does anyone know if there is any difference in fitment between the OEM exhaust manifold of a 330i and a 330xi due to drivetrain? I found this on realoem.com: First I searched for "exhaust manifold" for a '02 330i. Found this: http://www.realoem.com/bmw/showparts...11&fg=50&hl=13 Then I searched for the same thing for a '02 330xi. Found this: http://www.realoem.com/bmw/showparts...11&fg=50&hl=16 Notice, there are different part numbers for the xi headers with cats: 18407514504 and 5 The 330i part numbers are: 18407514502 and 3 Also, the xi headers w/cats are more expensive than the 330i headers. Don't know why they would be more expensive or have different part numbers, but it does put up a flag for me telling me that something could be different. Anyone with technical knowledge who knows about this would be greatly appreciated! Thanks!