Darn good question!
As a noob I'm still getting a handle on things n54, I haven't yet had the luxury of expanding & cross-referencing what I've learned to the 55 platform.
I'm sure others here will be able to provide that info? I hope?.....
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1and1
135i - E82.N54 2009 BSM - MHD / xHP / DCI, PR CP & 7.5" Race IC / N55 mid & Borla
. . WL RSFI, Koni, Eibach & Dinan CP's, M3 CA's / EBC Red's & Firehawk 500's
X1 - E84.N20 2013 MGM - JB4 - The Wife's, now with new turbo & ewg