Buying a bike in USA, Mexico or further south
 

Hi, we're planning to travel around South America in a year or so. Originally we thought to flight our bikes from the UK to Buenos Aires... but.... considering the costs (been quoted 2500 pounds min. for 2 bikes) I'm wondering if it is possible to buy the bikes in USA or Mexico instead (or furtehr south: Chile?). Is it possible for non -residents to do so? Choice for us would be something like BMW650GS or V-Strom (I'd need something low and light).
Thanks,
Maria