The "Anchor" (for the ball screw) had almost 2mm curling on the corners printed at 0.2 with the large side down (original version), even with raft. So flipped it and added supports (version 3), now it prints flat and parallel. Better to use a little more material and have a usable part. FWIW, I'm printing PLA and don't have a heated bed on my rep2.
Thanks for your comments :)