Aye! Get the beast working properly first.. it's a pity to spend a load of moolah on it and then find out it fails its next MOT so you then have to find even more money.
Once the beast is ship-shape, the first thing to do is the wheels. since the body kit may make the regular wheels look a bit puny. You want 18" or more and slightly less offset so that they stick out a tiny bit more. Don't mess about with spacers... just buy the "correct" offset wheels.
Then your discs will look tiny and the calipers will look ****..

so you need to get the calipers painted at least and get some trick rotors. If you happen to win the lottery, look into what bigger calipers and discs will fit. Someone somewhere will have fitted brakes off an AMG Mercedes to their Stilo. You want something equally enormous.
Then you need a bigger exhaust with a twin pipes, DTM styley flick-up... ideally angled slightly towards the kerb rather than straight out the back... with a metal heat shield on the bumper.
That'll do.. because by now it will feel chronically slow and *nobody* (even a lottery winner) can make the 1.2 demon-fast. So you'll only want to fit accessories that you can lift to the 2.4 Abarth model that you'll want to replace it with..
Ralf S.