Well I already have a D30HP w/ matching gears. So I guess I have a start. It has the smaller U-Joints & CAD. But I'm ok with that, I'm looking at doing a D30HP or D35TTB as a build up/project with no time frame. I live for this stuff.
All you have to do is swap the shafts and plug the CAD BS to move to the good shafts. I would do a D30 over a D35TTB, if you ever decide to move to a bigger axle IE a D60 most of what you need is already there.