Have an Audi estate (A6). Now 5.5 years old.
There is no way you could fit 3 car seats in the back. We have 2, and a tiny gap between them. We've tried fitting 3 (2 big ones and a booster, various types belonging to cousins) and it couldn't be done. You can put one in the front seat (airbag can be switched off easily) if need be.
Our Audi has been a PITA and a money pit. It is forever going wrong. In the past year it has had steering realignment (twice), new brake pads and discs (twice), new key fob batteries (twice - £60 a go just for a battery, compared to £4 for a Ford one), complete set of new tyres, something expensive done to the suspension whatsits, etc. At the moment it also needs the electric windows replaced (approx £600), a new parcel shelf (old one broke - £400), and has gone all sluggish inthe past couple of weeks (no doubt big £s involved). It is in and out of the garage all the time.
We've decided to call it quits and trade it in for something altogether more reliable and cheaper to run, but still an estate.
Audi parts and labour charges are very expensive, and the staff at our local dealership are quite rude and patronising (say things like 'shouldn't you run this by your husband' when I go in).
Rant over.