[Janne Kokkala]

You got to be specific mate. 
When do you lose control? 
- Corner Exit? Corner Entry? Mid corner? 

- While accelerating? While braking? While coasting?

Whenever I turn the steering wheel for a slow or a fast or a mid-speed corner, it feels like the car starts living a life of its own, and throughout the corner and when I try to straighten it after the corner, I often have to spend a few seconds making corrections.

I don't understand why  you'd experience that with the BMW or Merc (I never drove the Alfa). They're pretty conventional to drive.

But my first thought is to check you steering config. It sounds like you may not have 1:1 steering but something closer to go-kart steering ratio. It doesn't sound like a setup problem.

Or maybe it's a FFB setting as that can be customized for each car.

That's certainly very strange to hear. For me they are completely different than any other car I've driven in AC. The in-game steering wheel rotates exactly as my real-life steering wheel does, if that's what you mean. I don't remember adjusting any FFB settings for the cars and it would be odd if I accidentally managed to destroy the settings for just these cars specifically but no others.