Hi leia74,
I have never put Moroccan Oil on before I colour but I have coloured hair which as Moroccan Oil from regular use and had no problems, if it is very porous I think it does help, the company say it does stop fading. But I have also shampooed hair that is over loaded with Moroccan Oil before I colour because it seems to 'full' to colour.
I have never used it when perming - don't do that many (thank heaven) so not an issue for me.
Hope that helps a bit, will be interested to hear other views/experiences.