I sold mine a few years ago, then bought my 82 sc. I had 3 different quattros.
I sure don't miss working on it all the time.
They are fun, but the 911 is more connected to the road, I'm my opinion.
I put an 87 5000 turbo quattro engine in, and stand alone efi, it was very fast.
But still understeered.
I discovered that Audi was not interested in supporting the original urq.