This video series will go over the process of retrofitting a E90/E92 335i n54 ON 3 single turbo kit to work on a e60 535xi. The typical things for a single turbo install applies for this application also, but there are a few caveats to keep in mind. This is all a proof of concept, and I wouldn't recommend going through this process, since its untested. Give it some real world driving and can give more insight. But all in all was a great experience since it was a simple unbolt and bolt on new part project.
