If you want to enclose your V-Core 3.1 then ABS will get you higher temperature resistant parts. This whole set of files is optimised to be easier to print with better looking results when using ABS.
General Change Goals
Improve printability especially for ABS.
Printed parts to require no treatment after printing
Screw insertion to never require force
Common Changes
Low layer chamfers changed from 45degrees to 63degrees
Screw Hole diameter increased to be 0.5mm larger than Metric size