...you getting an urge to keep that lovely crane engine assembled, instead of pulling it apart right away, since you´re asking 
You Nailed it Jan, I have over 2 hrs of run time on the all black D405 and am getting mighty attached to her!
Also I was correct, the factory steam pipe from the boiler to steam chest is soldered on factory built and threaded on D415 kit....I Can heat the solder but I just can not bring myself to cut into such a Nice engine!...So the NEW plan is to maybe just put a few tasteful dress up parts on the Black unit and do the D16 conversion on the kit...if the Conversion goes smooth, the Black one could get a D16 much later...but it might be fun to have Steam "pulls" to compare the power!