[007_e350]

Originally Posted by Snertz

You'll also need a DME for an N54, along with new turbos, dp's, intake, wire harness, etc. The manifold studs are different between the two engines hence N55 turbo won't fit, along with the N55 having different injectors, valvetronic, etc; Most of the stuff won't be reusable with a N54.

You're best bet is to either have them replace with another N55, or source one yourself. Like someone else mentioned, dealing with emissions amung other things will be a pain; some of the crazier swaps are likely running on a standalone to get around the coding and wiring issues.

+1 stick with N55 ... lot of electronics involved to do a complete swap without any issues

[IK6SPEED]

why not source a n55 head yourself and have a shop do the install. its not that hard, i changed a head on a 2011 n51

[froop]

Don't forget that the transmission and propshaft are also different lengths in the N55 compared to the N54 so that would likely need to be researched and maybe replaced entirely.