With a modern Fiat/Alfa 1.9 turbo diesel, this would have been a worthwhile exercise (150bhp, mappable to 170-180, so nearly as much as a stock 16VT, but with much better torque) - the car would have sold easily with the later lump, but it would have been a significantly harder build
I've been pushing the idea for years, but it might have to wait until I retire
It's not easy because there are so many CANBUS systems in the Bravo (and I assume the other cars that carry it, like the Alfa) that you'd almost certainly have to transplant the entire wiring loom. And I'd probably want to do the steering wheel with the remotes, phone interface, and clever switches which are a definite improvement on the coupe's.