I made one little mistake with those tables, which is I forgot the rake limit... Shift+F5 to the rescue!
They do take into account the bodyaero and diffuser though, Kennet. I only specified the wing angles in the test because they're adjustable in the setup, whereas we can't do anything to affect the diffuser's downforce other than ground clearance adjustment.
Stalling occurs at 1mm ground clearance, so is off the edge of the tables.
You're right about ride heights and drag though. It does increase the higher you go.
Tables of that to follow!
Drag coefficient, n of drag per (airspeed [m/s])^2, less is better
Aero efficiency. Lift coefficient / Drag coefficient, higher is better
Only thing not taken into account here is radiator and brake duct openings. So this assumes those are shut as far possible.
Still though, the downforce gained at those extreme ground clearances outweighs the drag we get. This all looks pretty mental to me, but I do wonder if this could actually work on track? Or is this car's aero perhaps tailored to conditions it'll never operate in?