I have citizenship ambitions so I'll be coming in with a student visa. I'm already accepted and enrolled and approved by the Ministerio de Educación for a 3.5 year program. I have all the needed paperwork for the visa but right now the consulado isn't processing them. So I'm just on the waiting game.If you are entering Argentina as a tourist (from a "visa free" country) please keep in mind that entry permit is for 90 days and can be renewed once at for an additional 90 days at the office of migraciones. You can stretch your stay for the 6.5 months that you indicated (or even longer) if you visit a neighboring country while your 90 day entry permit is still valid. You will get a new 90 day entry permit when you reenter and you should be able to extend that by 90 days at the office of migraciones.
You can only get one extension and you should not leave and reenter while the extension is in effect. Border agents cannot "override" the extension and will not give you a new 90 day permit if you return before the "prorroga de permanencia" (extension of stay) expires.
PS: Always count the exact number of days when calculating your departure deadline. It's easy to overstay an entry permit by considering it good for three months. An overstay is not a big deal, but there is a fee/fine (I beleive presently $4500 pesos) that is charged for an overstay of even a single day..