IIRC Authi's not allowed to sell their cars or race them in the US thanks to that Name confusion thing with Audi (and Audi's Lawyers.) So SEAT and Santana are having to do all the heavy lifting.
That's weird - Audi is pronounced /ɔːdi/ (AU-dee) and Authi is pronounced /aʊθi/ (OW-thee) - in other words, the two marques are pronounced differently and hence there is no name confusion - especially considering that the logos, too, are different. Authi is allowed to sell their vehicles in Canada since the whole name confusion thing was seen as being bollocks, amongst other things.