How stable is the ingentis? Worth looking at beefing up any rods or 4 rods for z axis or would that be TOO overkill because its rock-solid already?
I fear instability, coming from a Mendel 
I’d say it’s overkill. Think of the i3 design. 1 smooth rod on either side to hold the entire X gantry and that thing has a moving motor on it.
It wouldn’t hurt to use 12mm Z shafts and bearings. But not really necessary. Might be worth considering aluminium, hollow 10mm xy shafts to reduce moving weight.
@Tim_Rastall I’d be interested in seeing that work. I’d be too worried that the aluminum rods would bend, or wear away over time with the brass bushings over them.
@ThantiK sorry, I meant with igus bushings or similar.
The ones I have on my current printer (1/2 " PCB liner ceramic coated http://www.essentracomponents.com/sku/PBC-1052 ) work like a dream. But you can’t use roller bearings on them. They won’t flex. I will be using these on my ingentis variant potentially. But I will have to turn the ends down for the pulleys I just got in the group buy.