my user shapes are all one color. I'd like to change the color of some of the pieces in the shape (have a 2 colored user shape). Is there a way to do this?

It would requiring some testing in a test model, but you may be able to BEDIT the usershape to change the layers, or edit the usershape.dwg linked to the spec.

If I remember correctly, user shapes are treated as a unitary 3D solid AutoCAD object, not a block. That means there is no direct means to have a composite object with different settings like layer or color.