I can't give much advice on bringing parts in person through Aduana. Last time I went through I got pulled up by an officer and told I had exceeded the US$150 limit on purchased goods. I pointed out the limit was US$300, I even had the AFIP page on my phone screen as I had been doing the research the day previous, and the agent acquiesced to let me pass with just a warning.
Such experiences have led me to avoid bringing anything of value through Aduana. You could try hiding a couple of graphics cards and processors in a small-form-factor case and bring them in as your personal computer, although I've personally never attempted this.
Re.
Getting parts into the country: you can actually order parts of any Amazon store in Europe and have it delivered to your door in Argentina under certain conditions. It may even turn out cheaper than European prices if you win the Aduana lottery.
This applies to any electrical product under 50 volts, pretty much any computer component: RAM, graphics card, SSD or HDD, Motherboards, cases, peripherals and cables.
The package weight cannot exceed 50 KG.
Package value MUST be under US$1000 (price of the components themselves, not p&p costs, although you may want to leave a VAT buffer - see end of post*).
Firstly you'll need a Clave Fiscal nivel 3 from AFIP and put your CUIL/CUIT number in the second line of your Amazon shipping Address.
Then on
Amazon.co.uk Amazon.fr Amazon.it Amazon.es Amazon.de search for your product and make very sure to filter results to those that are both sold by Amazon directly and qualify for Amazon Global Shipping:
When browsing products, ignore the "Does not ship to Argentina" below the product description. This is a bug.
Add your product to your basket and then go to the basket page.
Here you will see if the product ships to Argentina or not; on the right side with the VAT, postage and packaging estimate.
You will get the product VAT-free, which normally covers the cost of shipping, and you pay a +/- 40% import fee to Amazon, of which, if Aduana duties turn out to be more on arrival to Argentina, Amazon absorbs the cost of extra Aduana duties. If it turns out to be less, Amazon reimburses you. Many people report no tax at all on individual items such as graphics cards - hence paying less than European prices for computer parts. The average seems to be about 20% import duties.
If all goes smoothly, your purchase will arrive to your door via private shipping.
Here is
the Argentine forum where I learnt this from. There are some further conditions concerning regimen C and P that you should read here.
Make sure to read up on the latest posts to check on any news.
*S
ome shoppers have reported the VAT being mistakenly put on the shipping label by Amazon.es, even though it wasn't charged, leading to the apparent purchase to exceed US$1000 and problems with Aduana.