In the early 1980's, Ford made a very bold effort to try to globalise their design language. In simple terms, this should have enabled a very similar product to be sold in a variety of markets around the world and to an extent, it worked then and still does now. Thus, Ford would save millions on development costs. The Granada Scorpio of the mid nineties was taking the concept a bit far for most peoples stomachs though. So generic and bland as to appear gormless.
If you wind the clock back even further, things get a bit more interesting. In the 50's, 60's and 70's in times of post war growth prior to the European experiment, countries proudly flaunted their specific automotive wares internationally. In those days you could tell what country a car came from by smell and sound alone. There was even a chap on the TV that could workout what the make and model was by listening to doors shut blindfolded, seriously! And just think back to what the Americans were up to in those much less integrated times, They were out of control, in a good way.
Today, there are many companies that are acutely aware of brand heritage and national identity. BMW owns both Rolls Royce and Mini but are wise enough to base those brands in Britain and to celebrate and promote their British identity. This is palatable and works very well and will probably continue to do so regardless of whether or not Great Britain remains in the EU.
For me though, I liked it best when the French were driving across ploughed fields in tin snails with an unfathomable gearbox and a dozen eggs in their top hats, so much so, that I have owned two 2CV's. I liked it when the Swedes made big, safe,bomb-proof tanks, so much so, that I have owned err... five ish. And don't get me started on the Italians. 288 GTO anyone? I want to encourage diversity, even quirkiness and eccentricity, the world is a richer place for it and for that reason alone, I will vote for independence, I have a few months worth of debate to endure first though.
Better together? I don't think so.