Not really easy, they work different, ballast has different control pins, some cable modification inside lamp close to ballast is needed, also bulb doesn't fit, bulb or lens needs to be modified, this is easy part. About ballast, this is how i compared 2013 US model vs 2015 EU. Maybe 2015 don't...
The reason you need to wash the lights (idea of this regulation) is when you have dirty headlight, it makes light distracted and it makes other drivers to go blind. But this idea is wrong since even original high pressure washers are not able to wash dirt from headlight. That's why this...