We do things a little differently. Our base PPi is free and takes about 1 hour.
visual body inspection, tool kit, spare and condition, battery test, cooling system inspection, Belts, AC, basic safety stuff(srs light, tensioners etc.)AC funtion and flap test, horn, lights, steering, suspension, brakes, subframe mounts, flex discs, oil leaks, water leaks, look under carpet in front for flood damage, trans fluid level and condition, state of service (yeah, this is a wild ass guess but, you can get a clue if the last 30 was done or not)all interior accesorys, door checks, windows, ATA if equipped, CA if equipped, CF if equipped, OBDll codes (on obdll cars of course :-) ) wipers, tires and sunroof. Other things such as rear headrest release, first aid kit, audio systems, rear sunshades, convertable tops, hardtops and so on vary by model.
The idea here is more or less a PDI just to be sure the car you are looking at is not a dud, further diagnosis can be approved for compression tests, a/c diagnosis, drivabilty etc.... Face it, even the finest PPI will not unearth everything, however just getting the PO to allow you to take it for a PPI is a part of the battle.
Just for a example, I looked at 126 body 300sd today for a client, free of course and found about $1200.00 that needed attention now and one openended deal with the a/c, (works but not cooling) most of it was little stuff but, there was about $600.00 that was noted as future needs in 20 to 30k with the suspension. He bought it and got a little better deal as the car needed some attention. (you oughtta try and sell a car with no a/c here this time of year, can't give it away) There again, he now knows that most of the car is worth having, however the motor could blow the next time he cranks it.
No PPI will assure you a car that has no suprises in store for you, but at least some of the issues will be know prior to you writing that check.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.