I did what I'd usually do for buying any car. Ask them to put the car up on a hoist. I was looking for any obvious leak, including checking shocks. Take a quick look at tires and brakes. Then, I check body panel - any obvious panel alignment which suggests body repair. BTW, I notice front bumper uneven gap on some cars that I've checked before - I don't know if it is typical Lambo build quality issue or those cars have had front bumper removed and not put back properly - seem pretty common.
Really, I rely on PPI to do most check. I just did the above brief checking to make sure I am not going to waste time and money on any PPI.