Are you sure this is a Twin Air and not a T Jet?
Twin Airs have wierd hydraulically operated valves (a sort of camless, hydraulic system, trying to do Desmodromics on the cheap) on one bank, while the T Jets are turbo developments of the Stilo/Idea engine (as seen in the 500 Abarth, Punto Abarth, etc).
T Jet Centos are known to exist in Poland, and, I think, there's one in France. Any decent aftermarket ECU will run them .
Note, though, that the Punto Abarth (and the Mito is just a Punto in drag) uses a different gearbox (actually, one of two different 6 speed gearboxes) to the 500 Abarth (5 speed Alfa box) -- turbo torque at Abarth 500 levels will probably destroy a 1108 FIRE box (C514) pretty quickly. For space reasons the old Alfa 5 speed box is the one to go for.
The turbo on the T Jet engines poses further space issues. Ideally, find something else, mount it above the gearbox.
Much of this has been documented here in various posts (even with photos). A search should find.