[Fish Fingers]

We have had a few Audi's. S3s / S4 / wife had TT. UK based also.

I don't think you will regret moving to BMW. They are far more driver focused.
Tbh, I didn't like any of my Audi's much. Quite rapid....but a bit numb and boring.

There used to be 2 Quattro systems. Traditional torque and Haldex. The latter wasn't so good imo.

Re X1:
We have recently got the 30e Sport for the wife in Portimao blue (great colour).
Brilliant car. You will love it.

Not sure exactly how the AWD works (I think it's engine drives fronts / motor rears)??
But we have never once struggled for grip. Even in the wet leaving a junction, it just grips and goes!
If you think about it, a motor on each axle should give better control (if managed properly) than a single power source split between axles at varying rates.

Only real complaint from me is the steering is too light.

So don't worry about the grip. It's not an issue on the phev X1. It's incredibly sure footed.