Figured I'd share my header install experience I did on my '03 X5 3.0i this weekend. After getting fed up living with catalytic converter rattle I finally gave in & purchased these 'Doctor LAVR' M54 exhaust headers from a Moscow ebay seller.

They are custom made specifically for E53/E39 fitment unlike the usual cheaper E36/E46 ones typically found that will bolt up to M54 but flanges & angles will be wrong for this chassis.

The quality seems to be top notch. He included all gaskets & plugs/hardware required aside from the cylinder head studs/nuts which I picked up from the dealer.

As expected this job was a pain even on my work hoist but the fitment is perfect. One cylinder head nut I had to could only get on with an 11mm ratcheting wrench due to header tube blocking socket access but all others swivel sockets/U-joint worked fine. The headers are easier to work around than the factory cats.

The only tweak necessary was prying the center resonator pipes apart enough to get the flanges to match the header flanges. I didn't bother installing rear o2's as I might code them out of the DME. So for now CEL is on.

The exhaust volume went up exponentially with the headers & rear mufflers removed previously. It sounds very aggressive on startup & deep low down but gets obnoxious past partial throttle. I picked up some e53 4.4i N62 V8 rear mufflers to throw on & maybe modify. The catless exhaust smell is noticeable at times but way less than I expected.

Overall I am very pleased. Highly recommend these if you don't mind going catless on the 3.0i.




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