Looking to get a 2.7T A6 or Allroad - What to watch out for?

Hi All,
I'm seriously thinking about getting into an Audi A6 or Allroad, as a
performance oriented large-ish car with a manual transmission. The 2.7T
drivetrain + 6-speed + Quattro looks like a winning combination.
However, from what I see on Consumer Reports and the like, there's a
reported reliability problem.
Of course, I'd like to minimize the cost of owning the car, as I'd imagine
that Audis, like other European makes, have relatively expensive repairs
(I've driven Nissans for the last 4 cars).

Hopefully someone can set me straight, or point be to a good website or
forum. The main things that seem to cause expensive repairs have to do with
hose/valve/gasket failures, and dealing with the longevity (or lack therof)
of the turbos.

Are there any good solutions for these problems? Are there any others that I
should be aware of?

It seems that turbos eventually have to be replaced, but my question is
when? At what mileage should an Audi A6 or Allroad be considered as a less
attractive option due to wear/tear?

If/when the turbos need to be replaced, it looks like a good opportunity to
go in for all kinds of potential upgrades such as RS4 replacement parts
(turbos, intercoolers, clutch, flywheel). Is this worth it, or will it end
up being too much stress on the car? Anything else I should consider?

Any info greatly appreciated, as I'm trying to understand the true cost of
getting into an Audi, and after making it as reliable as possible, looking
at performance upgrades

thanks