wanna see a picture of the volute...not holding my breath though.
IIRC the D5 and D4 had a very intricate and specialised design in the "top".
This is more than likely just like the DDc top from koolance which misses the mark in everything except style.

So now the D5 can intake from an off-center location? The impeller's intake is still dead center....wtf koolance?