Becoming an Agent/Reseller

Well for starters import duties, costs, minimum volumes / sales they expect / you expect the market can be done (and keep in mind parallel import by someone else and people buying directly from USA), after sale support (EU's rules are stronger then US and you'll need to support EU regulation and take the cost for that support), how to deal with decommisioning of the items (you have to take them back if you sell them directly).

Then once you're aware of that and want to proceed you'll need to think of legal form you want to set up the company, amount of cash you need to float (paying of units on way and in storage, VAT, import costs, over heads, storage etc.) and how you're going to get them out on the market.