It depends. One on one, a scrab would easily win due to sheer speed and strength. But if a pack of say, three or four paramites approached, I think they would win. Paramites are slightly more intelligent than scrabs and will work in packs to catch their prey, almost like hyenas.
Scrabs on the other hand aren't very smart - they are mostly instinctive killers. They can't seem to be able to work together in groups either. In AO we always see scrabs slaughtering each other to prove their dominance. On second thought, I think that a strong scrab could still win, even against multiple paramites. So I'll go with the scrab.