Horizons Unlimited - The HUBB - Advice wanted for buying a bike in Bolivia

My Girlfriend and I have just started our trip through South America. We flew into La Paz, Bolivia a few days ago and our original plan was to bus down to Chile to buy a bike there. From there, we planned to work our way north to Colombia over the next 7 months. We would then sell the bike and fly home to Canada in April. Our reason for planning to buy a bike in Chile was because of the advice we found on the HUBB forms which indicated that Chile had the most straightforward process for buying bikes.

However, on our flight to La Paz, we sat next to a friendly man who makes a living importing bikes from the US and selling them in Cochabamba, Bolivia. While he doesn´t have any bikes to sell us, he has kindly offered us a place to stay and to help us find a used bike as he has many friends who would likely have something to offer.

This would work well for us as it would save us busing all the way to Chile and we would also have a friend who could help us with the process. However, we are concerned about being able to leave the country once we have bought the bike as well as being able to sell it in Ecuador or Colombia once we have finished our trip. Our friend claims that the process would be relatively simple and we would be able to buy the bike from a Bolivian owner and leave the country within a few days. This seems to be an easier process than buying a bike in Chile but we are worried that our friend might be mistaken.

I have searched the HUBB and the web for topics related to our situation but cannot find much relevant information. Does anyone have any experience buying a used bike in Bolivia and taking it out of the country or know of any resources that have information regarding this? We are wondering what sort of paperwork we would need and how we would go about obtaining it. Any help would be greatly appreciated as we hope to either buy a bike here in Bolivia or leave for Chile within the next few days.

Thanks!