I printed a 20mm Z-ABS test cube before starting to install the Z-Temp mods, then again after the Z-Temp unit, bed heat switch, ZT-HE and the insulating blanket were in place. For the latter I sliced with the Z-ABS profile then used zero Z-Temp offset and full bed heat (position 3). Admittedly, 20mm cubes aren't the most stringent test but if there is any significant difference between the before and after cubes and a baseline cube I printed weeks ago I can't see it.
In the attached photo the baseline cube is on the left, before is center and after is on the right. If anything, the one on the right looks very slightly better under a glass. All three measure the same with sides being an avg. of about 19.949mm. Close enough!