A quick 'check-over' at the roadside is not a pre-purchase inspection. A proper PPI takes 60–90 minutes on the hoist, involves dealer-level diagnostic scanning, and produces a written, photographed report you can actually use. It's not a courtesy check — it's evidence.
The car goes on the hoist. Underbody, chassis, suspension, drivetrain, exhaust, cooling system, oil leaks, transmission pan, differential — everything you can't see from a driveway walkaround. We photograph anything of note.
The car goes on the diagnostic tester — ISTA, ODIS, Xentry or PIWIS depending on brand. Every module gets read. Stored faults, pending faults, cleared-code history where the tool exposes it. On some platforms we can also see service history from the module (odometer at last service, what was actually reset), which sometimes contradicts what the seller claims.
Then the road test — cold-start behaviour, gearshift quality across the range, cruise, braking, alignment, noise and vibration under load. Not a two-minute drive around the block. A real road test that stresses the drivetrain the way a real owner will.
Finally the report. Emailed same business day. Plain-English, photographed, honest. Written so you can hand it directly to the seller if you want to negotiate — evidenced findings, not vague opinion.