A criminal waste of a wonderful car. It simply is NOT for short commutes so buy something else C1, Panda, Yaris, Fabia, Dacia! etc.,.
Short commutes will mean turbo hardly ever kicks in, EGR will be v unhappy and DPF will fill up and fail since it will never regenerate.
You are lucky to get 30mpg on short commute but on longer journeys at near legal speeds +++++ you should get 43/48 even if averaging 'over the limit.
The trick is to get it remapped. All cars come out of the factory with the factory map which has quite wide tolerances so it can cope with a wide range of scenarios.
A remap costs about £350/400 (from a decent engineer - dont go cheap and dont forget to ask him/her where he/she learn his/her trade.
I had my 2.4 JTDM SV remapped and they put an extra 40 BHP on it. Standing start still not much difference but mid range brilliant, excellent for getting rid of tailgating Golf GTI baseball cap wearers. Have never taken it to the limit though - bottled out at 125 mph on a German Motorway with a Merc AMG S type tailgating me 4 feet away!
Also don't forget to change the oil and dont go cheap it's a £30,000 motor (when new) so £100 on an oil/filter is peanuts.
Finally, remember, the Brera is NOT a car, it's a WORK OF ART so be gentle with it and treat it with care. Do this and its bliss, forget it and it will bite you in the wallet.