needing a new ecu

[bloaby]

hi i recently went to start my peugeot 406 hdi and it wouldnt go took it to the peugeot dealer who done a diagnostic check an came back with a £1600 estimate to repair my car for a new ecu and ignition switch, surely i can get it repaired cheaper, if i get a used ecu will i need to get it remapped? will i need to change the bsi if i change the ecu? and where is the bsi if i do cause cant find it