Okay so I'm looking to buy an a6 I have an okay mechanical knowledge I do my own repairs and maintenance so the cars I'm looking at have from 100-130k miles cheap cars though. What should I be looking for? Any warning signs I should know about?

All of the cars are stock the one particularly cheap car has a "slight" coolant leak and needs brakes and rotors I haven't seen the car but slightly concerned about the coolant leak should I be? Replacing the reservoir did not fix it

 

Could be any of the multiple water coolant hoses. I just repaired my 2002 Audi A6 2.7 and replaced most of the coolant hoses. What you need to be aware is the hoses tend to expand and contract over time. You may want to check all the hoses. My Audi was in the shop for a replace transmission and we changed all the hoses and still had a big leak. We had to take apart exhaust manifold to get to the hose. We ended up replacing 2x 6 inch hoses. Do you know what else was repaired on the car recently? Any ABS or other lights on dashboard on?