Shopping at the airside stores at EZE is overpriced, so I'd just as well recommend shopping in town itself if the opportunity is there on another day.

I don't expect traffic to be that bad along the main road in front of AEP that leads to the center. The traffic from say near Plaza San Martin to EZE? Well I don't bet on that.

Make sure to remember that after check-in you have to pay the departure tax before you can go for security screening and departure passport control.

4 to 6 hours of built-in transit time would be more advisable, but perhaps that is water under the bridge at this point.

Is the LAN flight into AEP on the same ticketed itinerary as the flight departing EZE? I hope so.