You can actually print holes for screws as small as M3, even when using normal screws and not selftapping Also ABS is no problem for screw holes.
I have no experience with PLA but my ABS prints turn out fine and the threading seldom strips.
Just make sure that you print the holes about Ø2.5mm (nominal diameter - pitch) this only applies to 60° threading ie. Metric, UNc, UNf, UNef.