Although new to this forum and to Alfas, I am a bit of an old dog around engine building and tuning and have come across this so many times, I thought twice about posting as this topic can get a little heated.
There is no perfect map for any particular car, and I am talking about individual cars not a specific model. There are so many variables from fuel octane rating in the tank at the time of the map to the ambient air temperature at the time of the remap ( assuming a live remap was performed ).
So asa basic start point, make sure you have good clean reliable fuel in your car at the time of the remap, as well as the oil being of the correct viscosity and be at the right level ( not filled to the top mark on the dipstick ).
Any aftermarket parts that you want to fit should be fitted before the remap is done, yes I know its obvious but you will be amazed at what has been asked of mappers, ' I'm going to get a full decat and big bore kit, can you map it for these before I get them?' I am not kidding!
And get it done on a day with a reasonable temperature, not in the middle of winter and not in the middle of a heatwave either.
On a standard car with the 'cat' in place and the standard airbox a remap should as a couple of guys have said, give you a smoother power delivery, a bit more midrange ( I did say a bit ) and very little at the top end.
The biggest problem with any modern car is the cat! If you want more power, better fuel economy and a smoother faster power delivery 'ditch the cat'!
Mappers get a hard time sometimes, mapping a standard car ( petrol ) is possibly a waste of time and money, but that is up to the owner or bill payer, yes you should notice a difference, even my wife notices a change when I have been 'playing', but I would suggest get the intake and exhaust sorted ( including ditching the cat ) then get the car remapped, then you will notice a difference.