I know exactly what is takes to swap an S54 into a non-M, done it myself.
Mo assumptions are made here.I saw your car in person at the bimmercruise and I was not the only one to say that it wasn't running well. Almost everyone who heard it run said it was way too rich . Like I said, if its all good now then I'm glad.
To me 2 months to install an S54 and HPF kit is outrageous, if it satisfies somebody else, I'm fine with it.
No jealousy here, I'm just stating what I know.