Difference between MBL "D" and "E"?

Can anyone explain the difference between these to series of dig. equip.- what does the E version have that the D does not and also how much to upgrade the transport and DAC from D to E- bill
Agon member bluetrump carries the mbl line in the US, Im sure he could answer your questions.
as could bill parrish of gtt audio in new jersey...great guy!