Looking to change my ECU to one i recently got on ebay. If i swap it, do i need to worry about the smartlock or key/fobbs? Or is all that managed by the BEM?

if your just chainging the engine ecu? there is no need to worry about the key fobs ect,
as its the bem that does the central locking and sends the signal to the ecu...

so you can just plug in another ecu and away you go...

awsome, thanks mate