Lots of expensive problems with the old Audi A5 convertible. You can see them all here: www.honestjohn.co.uk/carbycar/audi/a5-cabriolet-20.../

Important to note that the costs to service and maintain this car will always be relative to the A5's price when new (£40k) and not one that's now worth between £8000 and £10,000. Personally, this is not a car I'd recommend. But if you buy one, make sure you have lots of money in reserve for the issues that will inevitably arise.