F&I (and whoever he was prior to F&I) is discussing the issue from a childlike perspective.
You're making wild, ludicrous and specious comments and claims without an attempt at validation from facts, figures, data, or support from political/commercial experts, (except for imaginary social media.) You're repeating previous discredited claims as though they'd never existed.
But we will be free to trade elsewhere in the world, we can devalue Sterling to make British goods cheaper on the global market.
If we devalue GBP it will make our imports more expensive. That's imports of raw materials to create our products that we then hope to export. We don't have all the required materials, nor can we produce them as cheaply as we can buy them in. Therefore, our products would become more expensive. It's a merry-go-round. In addition, we'd still have to buy so many products that we can't produce, so our cost of living will rise, which will in turn mean that we can buy fewer things, which means a down-turn in our economy, loss of tax revenue, loss of government spending, loss of infrastructure, etc.
Where will the EU offload tens of thousands of motor cars?
The answer is so simple: they'd be competing with us for increased market share. Except that we'd be looking for new markets, they'd be looking to increase market share with existing infrastructure, dealerships, servicing, parts, etc. Additionally, our exports will have then experienced a sudden hike in price compared to their exports.
The big manufacturers call the shots in the EU so tariffs are pretty unlikely...
The EU is not an isolated entity. It is a product of 28 national governments. For your assumption to be accurate and true, it must also apply to UK government. In which case Brexit is a foregone conclusion. We're staying in!
Additionally, we've already discussed why EU would apply their import tariffs. If you choose not to read it, or ignore it and refuse to respond, that's your problem. Like I said, you're discussing the issue from a child-like perspective, refusing to read or respond to the counter-arguments.
But the imposition of tariffs is what you are hanging your entire argument on
Nonsense. That argument has already been dismissed forcefully. If you haven't read the counter-argument, and are resorting to repetition, that's your problem.
Moreover, the only issue in the Brexit argument is immigration. There is no other justification for Brexit. Sadly, Brexit would exacerbate the immigration issue, not resolve it.
Anyway, not to worry, F&I will invariably resort to pictures from youtube before long.