Okay, as far as the cracks, I've determined that it's due to switching from the Classic camera to the new Perspective one.

I was rendering a new scene with this object fine without cracks until I realized that I was still using the old classic camera (I usually use the new Perspective camera now for everything) - switching made the cracks come back!

So I'd imagine I need to report this to Newtek...

PS - So I guess what I'm still asking is, is there any way, Michael for MOI to adjust the normals for parts created by Mirroring? (I'm wondering now if MOI is set to render double-sided which would hide any flipped normals?...)

-Will