The list is long, hopefully i'll get there!
Things I've done…
Thorough clean inc door shuts/engine bay etc.
Stripped most silver bits from interior to be carbon coated.
Carried out full service inc gearbox, transfer box and diff oils (Redline oils)
Carried out full 4 wheel alignment… but at only 40,000 miles the front lower arm bushes are way too soft for my liking allowing movement that can be seen with the gauges on it.
Removed centre exhaust silencer.
Opened secondary cats & removed internals.
Reflashed ECU, (these mods have taken almost 1 second off the 40 - 80mph time

)
Planning to do...
Coilovers.
Wheels/tyres.
Certain bushes (Alfa should stop copying the bad bits from BMW lol)
Clean & paint brakes, fit uprated pads & maybe discs.
Tint windows.
I don't like the grey under the dash & door cards so thinking of dyeing it, undecided on the grey on seats yet.
Steering wheel (the one with red stitching from I think the Ti)
Satnav.
Reform the foam in the front seat base as its too hard for my liking.
Then… the engine might get my attention….
Not sure if anyone on here knows me but, Im well enough known in the Jap tuning circles having built numerous 6, 7 & 800bhp skylines, 1100bhp 2litre Evo 8 drag car as well as plenty other models including (dentist mapped) tuning the R35 GTR to over 600bhp as soon as the UK one was released.
I also built a 3.0 V6 Alfa 155 years ago, which reminds me, I still haven't finished my 2004 156, it currently has a Fiat Coupe 16v turbo engine in it

So I wouldn't mind tuning the Brera a bit more, forced induction will be the way but need to learn a bit more about the management & limitations of the direct injection first.