Alfa Romeo Giulia

One upgrade that helped throttle response a lot on the 2.0 is Centerline's wastegate arm. The OEM arm is just metal-on-metal on both sides, and wears over time (eventually it will start throwing codes reportedly). Centerline's arm is made out of titanium and has a ball bearing roller on both ends.

I found that the original arm was moderately worn with 63k miles on it (there was some play on both ends). Also, the rear pivot, which you can only move by hand once the wastegate arm is removed, was a bit rough in action. I lightly oiled the rear pivot point (not sure it's safe for the internals to soak it in oil) until it moved smoothly, and then installed the roller bearing wastegate arm. The engine hunted around in engine speed a bit for the first couple minutes (I'm guessing the ECU was adjusting to the more freely moving arm, or maybe from me moving that arm by hand several times). With the lubricated pivot and upgraded arm, the car is far more immediately responsive to throttle. I didn't expect much improvement, but it wasn't subtle at all.

A few different companies make "upgraded" wastegate arms, but I'm pretty sure Centerline's is the only one with ball bearings (and also titanium, though I'm not sure the type of metal makes a huge difference once you have the ball bearing pivot).

https://centerlinealfa.com/catalog/wastegate-rod-giulia-and-stelvio-20
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Some Giulia Ti Sport laps at Lime Rock ...