A5 3.0 TDi - a good risk?

I'm shopping for a car with a bit of performance and have stumbled on a 2009 3 litre diesel A5 S-line.

This car (and ones like it, though S-line is not common in Perth) seem like a LOT of performance and comfort for about the same price as a so-so MX5, 86 or Zed. Obviously they are very different cars but I am still narrowing down my selection.

Am I missing something? Are they a lot of trouble? They certainly don't seem to hold their value from new so I appreciate it might, er, depreciate..

Any specific issues to watch out for, or model years to avoid? Major maintenance hurdles? Are they actually as fuel-efficient as they claim?

Is the S-line pack a big selling point? If it handles better I would prefer that.

There is a nice-looking 2012/13 for a similar price. It seems these cars get dailied so there are not many with low km. Is there a threshold mileage I should stay under?

Many thanks.