Used Phaeton – what do I have to pay attention to?

Hello, I’m looking for a 2nd car with four wheel and comfort and have decided for a Phaeton. It should cost up to max. 20,000 EURO and the model should be at least the one with 232 hp – better the current one with 239 hp. Running power, well, of course, the less the better. But it will probably be around the 80-100 T KM. Warranty is of course. What do I have to pay attention to, so that I can fish small rivets here? I am grateful for every tip! VG Michael