Either get resdiency through the RADEX system of migraciones or hope Bajo_cero2 is corect that the pregnant Russian women case has set a precedent that it is now possible to actually claim residency by saying that you live here.
For the time being, I imagine that coming and going as you please as a "self declared resident" would be "challenged"at a port of enrty, but, faced with with arrest and deportation for "abuse of the tourist visa" by migraciones I would certainly give it a try.
YouMmoon is still around, but you may not realize that the last post in this thread was ten before yours was over eight years ago.
Here is a recent thread about getting the 90 day extension:
I wanted to let people know how I recently (yesterday) extended my tourist visitor visa so others can benefit and have more information about the process. I went to this office at around 9 am yesterday (Friday Feb 25): Dirección Nacional De Migraciones Av. Antártida Argentina 1355, C1104 CABA...
baexpats.org
What category of residency are you considering?