If you go for a plug and play like jam, blitz, mines etc.. You litterally remove the negative end of the battery... Plug the new ECU where the old one was and then let the car idle for 20 mins and drive it. They become fully responsive after 100 miles or so. A piggyback like emanage will need to be mapped by a tuner like Tuning Developments. A FPR and FCD option will need to be set up properly on a rolling road with a wideband to make sure the fuelling is right. Hope this helps, Matt