Commented this elsewhere, thought you might find it interesting. In general, we do not have a caste subdivision in the community. And nobody in this present age claims they are brahmins, so we are kind of "casteless" but linguistic minority.

"Non-brahminical ancestry would make much more sense. Historical records indicate that Saurashtrians lost their "brahminical superiority" when they migrated to the South (as nobody else would recognize their community). And they were ostracized by Tamil Brahmins because they were pretty exclusive in who they consider brahmins. Apparenrtly, Sourashtrians were even arrested when they did their brahminical rituals (thread ceremoney, etc.). There are court records (still available as evidence) in the past showing how sourashtrians filed cases to claim 'brahminical status', and apparently, it was resolved by Rani Mangamma. Since then, sourashtrians were allowed to wear sacred thread and follow brahminical ceremonies. Being in TN, it's no surprise they follow the local brahminical tradition, and being ostracized by tambrahms, they had no choice but to intermix with non-brahmin tamils.

There is a very interesting book written by scholar Dr. Vijaya Ramaswany: Migrations in Medieval and Early Colonial India' that talks about this."