If theres a stickie for this apologies in advance,

Im looking for a buyers guide, what to look out for on an Audi (ive got 5k, looking for a model around a 54 plate)...

test drove 2 so far, on one the turbo whistled rather loud, on the other the turbo was quiet, not being a car buff im not sure which one was to be avoided (if any)

ANY help would be gladly appreciated.