Re: 145 keys
It's a good haggling point. There are 2 possibilities.
There are circumstances where your ECU will forget the indentity of the red keys. This is rarer than bottom end failure, cambelt failure or many other ailments that an Alfa can suffer but if it is going to happen it will be when the battery goes dead, so avoid running it on a weak battery.
The burgundy key is used to allow the ECU to relearn the red key identities. Once you are in this situation you will need to send the ECU and code box off to a specialist and the bill is around £200 ish, or you can replace the ECU, code box and keys from a car that's being scrapped for about the same from a breaker, or better still wait for a cheap one to come up on eBay and put it to one side just in case (this is what I did- it cost me £15).
The labour involved in an ECU Code Box & Lock swap is around an hour. Somebody on here recently swapped the insides of the keys quite easily which would mean no need to change the locks.
If you lose a red key I believe a lot of key cutting places can copy a red key and the key code at the same time, so no need to reprogram the ECU in this instance (Please correct me if I'm wrong about this one).