I have an acquaintance from Australia who does export business here. He buys antiques here and ships them out to Australia and other countries to sell. he's been doing this for quite a long time. He fills containers (usually a couple per year I believe) and tries to do everything above-board, with all of his i's dotted and t's crossed.
He has lots of horror stories to tell about the greedy folk in Aduana. They always want money. He has a local expediter that helps him here and pays all of the coima to the right people that are required to get shipments out. He's not doing anything illegal, it's just a matter of greasing palms to actually get something out in the current year, for example. Without paying the coima, it would sit for months and months. He knows, because he's tried to do it without paying any money, bitching to those above the person he has a problem with, so on and so forth. He learned long ago you either cough up the coima or your stuff sits in the warehouse waiting for export approval.
That is just one of the problems. He has to deal routinely with people who just don't give a shit, people who regularly try to cheat him, so on and so forth.
He doesn't import, so I can't speak to that directly, but I would be surprised if that is any better, and probably is worse, considering how protectionist Argentina is related to importing goods. Aside from the high tariff rates on most things imported, you also have the coima issue with the aduaneros.
I'm not saying you can't make money at it. My acquaintance makes a decent living doing something he absolutely loves - he just wishes everything was a bit more efficient and predictable and less costly.
Just be prepared to spend probably ten times more than you figured before you get things figured out and start making money.
