Modern Vespa

Hello everyone! I recently had the opportunity to buy a wrecked MP3-500 LT (2018) with very low mileage. The frame and front end are bent, so I'm planning to install the engine and swingarm assembly into a 2009 MP3/400. The ECU in the MP3 is supposedly "married" to the master key via the ignition switch. As far as I know, the ECU programming of the 500cc engine differs from that of the 400cc engine (fuel injection quantity, ignition timing). Therefore, I want to install the 500cc engine and ECU together into the 400cc. This raises a question: does the ignition switch also need to be installed (from the 500 into the 400) or modified, or not? Mechanically, the 500cc master key fits perfectly into the 400cc ignition switch, but before I do all the work, I'd like to be certain. Piaggio themselves are being vague and haven't given me a helpful answer to my question. Who can comment on this?

The master key may fit in - but can it turn the switch? Uncessary anyway if you have both master keys and the service key for the 400. If you have these, just swap the RFID chip from the 500 into the 400 master key, then program the 500 ECU with both 400 keys.