Keys are left in the vehicles as far as I know and we do sell engine control units prices and availability of the vehicles are listed online at lkqpickyourpart.com and you can check compatibility as well called an interchange also available online.
Keys never seem to be in the cars, as for the ecu check the website it should have the list of available cars but that's never a guarantee they have the part you need but it will give you an idea if you should try to go.
Thanks! Your answer is awaiting moderation.