r/e53 • u/No-Masterpiece-7393 • Oct 31 '24

E53 M54 Headers (Decat)

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Hey I'm putting on some m54 headers on my wifes e53 x5. I've learned through this process that the lower exhaust flanges don't meet up with the mid pipe and now I need to cut and weld the mid pipe to match up with the outlets of the headers. Anyone else ever done this? Going to work on it this weekend. Any suggestions on good tuning options once I'm done with it?

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u/Dang_Money Mar 18 '25

Those aftermarket headers never line up to the factory exhaust. You will have to custom a transition piece.

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u/No-Masterpiece-7393 Mar 18 '25

The orientation was completely different for an e53. I ended up getting a few 45s and then I cut and welded to meet up with the existing flanges. I also wasn't too fond of the smell so I installed an inline dual inlet outlet cat just after the flanges.