I really like the contrast between the white hose and the dark brown color on the vacuum. Never knew some of the D2 models had insulation like that.

The Styrofoam insulation I found inside the dome of my D2 was custom formed for the D2.  I guess you could put flexible foam batting or something between the dome and the motor battle.  As for later models, I guess you could put the insulation between the outside over and the motor baffle.  But I think it would odd since you can see through it.  My blue E2 2-speed has sound insulation that's fitted the motor.  But again, it is custom formed. 

Rainbow no longer stocks and sells the bearings for the D2.  However, I know of one part supplier who still sells a replacement bearing plate.  You can also still buy the lower bearing from bearing suppliers when you know the universal number.  Also, you can't get the brushes anymore.  However, you can upgrade to the later D3 style brush holder and carbon brush.  In fact, Rainbow offers a conversion kit for that, which includes female spade connectors for the terminal wires.  When you're ready to service your D2, please let me know and I can direct you to the bearing suppliers. 

Here's link to the D2 bearing plate.  It's an aftermarket part, but it works just fine. 

Here's the lower bearing.