Originally Posted by Bmwbreed
I'm not sure if it does for you because you have an n54 car. For the n55 the harness is much easier to install as it just plugs right into sensors. The n54 harness was a bit more complicated and is mostly all installed in the dme where you have to swap electrical connectors and put different wire bundles together. But maybe if you had jb4 already and are just upgrading to stage 2 maybe it just plugs in to the map. Can't say for sure as I have an n55.
If I remember right the stage three for mine is the bundle of connectors like you said. I'm not sure though its been a while since I've looked at the JB4 stuff