they can and do come off no doubt, but having spoken to several specialists the best option in my honest opinion is to fit a brand new flapped manifold and at the same time remove the EGR. re-map optional but i could not go back to 150BHP in this car.
the flaps do indeed do the job they are supposed to at low down RPM increasing combustion efficiency and as a result power...
its not just Alfa, all of the marques that have used swirl flaps to get around this issue have reports of failure so its an inherent design issue,and improved intake design would help or maybe even a VIS like the fiat coupe has on the NA models..
there are plenty of engineering solutions to this that don't involve stuffing poorly welded crap into the inlet manifold!
the emissions controls have led to the lower displacement turbo petrol engines now being the choice for many manufacturers.
1.2 turbo petrol producing 130 BHP is normal! the afla 1.4 twin air is pushing 170BHP and could probably take another 20-30 safely and the 1.7 in the QV is pushing 240 and is probably good for close to 300 with the right mapping.
it will definitely be a turbo petrol for me next time around as it offers the best of all things, green,clean,fast and economical.
without the need for DPF ,EGR and swirl flaps...