these are a few top panel parts that you can swap out or replace with the originals before printing when adding on a Z-Rider by twotimes.
http://www.thingiverse.com/thing:4740 (z rider)
they are only cosmetic. the other ones will work but since i was no longer using the bearing holes, tensioner slots and stepper mount i decider to cut these parts out and replace them with the same parts but no holes.
print, take out old parts, glue in new parts, reassemble.