I know there's so much that you need to look out for when buying an S3.
I made a list of stuff to check over that helped when choosing my friend's car with him - We're picking it up later on today.
There's probably more that needs to be looked at, but thought that a good chunk of it would be useful to have written down in a checklist to take with us. There are other things such as listening out for knocking, getting under the car and checking condition, and so on and so forth..
But yeah this is what we took along:
Criteria Comments Temperature dial after a run Roof guttering - Rust/corrosion Tyres - Tread left? As advertised? Tax? MOT - Is it (X) months as stated? Previous MOTs to confirm mileage Clutch Cambelt/Water pump? When? Brakes - When changed? Discs as well? Advisories on MOT Clutch pedal? Any wobble? Check previous owners number matches HPI check - Make sure not written off prev Alloys - Check for curbing and corrosion Check all lights work Check for ABS/Traction Control lights >3kRPM Check for pixel loss on display Check stereo for issue with volume Check speaker grills for Bose signs Check gearbox - Notchy? Check for oil/coolant and make sure none mix Check for exterior damage/linup of panels Check all interior for rips/tears When was the last service? What was done? Any oil leaks in engine bay/under car?