I'm not a Mito owner and don't know a lot about the DNA system, but my opinion based on my limited understanding and some common sense is thus....
Both steering and throttle are electronic, and on DNA equipped cars the ability to change these settings will be managed on an electronic level, most probably by the main ECU. Although your model doesn't have DNA, it will still have electric power steering and fly-by-wire throttle I assume. Therefore I would assume that it would be possible to adjust those settings via the ECU.
So you need to hunt down one of the companies who know how to tune/map etc current Alfa ECUs and see if they can do this, or at least giev some guidance on what can/can't/may be done.
I have noticed on eBay that you can get an electronic device that plugs in to your throttle sensor and allows you to adjust the sensitivity. All it's doing it is intercepting the the signal and "multiplying it" so that your ECU is reading a greater level of pedal movement than what is there, and opening the throttle further accordingly. I don't usually trust all these eBay gizmos (2p resistors that can give you 10% more power, or magnets that you put on your fuel line to improve atomisation for better economy
), but the basic principle of this is simple enough.