Sinead,
First thing to watch for is clocking, these cars take the miles well and clocking is RAMPANT on Audis at the moment,get a hpi check done,make sure the car has its service book,preferably with dealer or specialist history,but any history is better than none.Avoid cars with all the handbooks bar the service book, UK car owners dont lose their service books as a rule, if its missing ,theres a reason......I'm not a fan of cars than were on longlife service intervals, these extended intervals can lead to the oil pick up in the sump clogging up and the oil pump failing( and possibly the turbo with it)
A well maintained S3 really is pretty bullet proof, if the miles are approaching 60k make sure the timing belt,tensioner and water pump are changed, the recommended interval is longer but 60k is when it should be done. All the coil pack issues everyone heard about should have beeen dealt with under warranty at this stage. Watch for cracked exhaust manifolds and turbo housings, only problem is you'd need to know what to listen for, you are looking for a more pronounced more hissy noise from the exhaust area of the engine bay when the car is ticking over,its difficult to describe the sound, but you make notice the car a bit less responsive to drive.
Front top mount bearings can go, they can knock and make the steering feel a bit iffy, only 7 or 8 quid to replace though.
Some cars had gearbox troubles, they are all a bit notchy when cold, but when its warm watch for a biting or grating when changing into 2nd or 3rd gear.
The rest of the transmission is strong, check in the service book for the oil and filter for the Haldex coupling in the rear diff being changed every 20k.
Brakes are ok(only ok, especially if the cars been chipped) watch out for corrosion on the discs especially on the edges and the inside of the rear discs, not mega bucks to replace, but use it as a bargaining point if you can.
Suspension again is only ok, cars still on original dampers will feel tired past 50k, so budget for replacement.
(think I have a set of 600mile S3 shocks here somewhere........
) Lowered cars need a set of adjustable upper tie bars to stop the insides of the rear tyres being eaten away in no time,if the arms arent fitted, budget for a set of tie bars or else be prepared to change rear tyres very often.
Go for a facelift model, the one with the one piece headlamp and indicators, 210 bhp or 225 bhp doesnt matter, you wont feel any difference in performance, the both can be tuned to 260bhp + so no point paying a premium for a 225. Both have the same electronic issues with MAF ( the engines air mass sensor failures common as are coolant temp sensors, intake temp sensors, exhaust gas temp sensor(expensive) etc, so a diagnostic check before you buy could be well worthwhile.
Watch out for some of the wacky interor trim, the lighter coloured alcantara doesnt age well if its not cared for, same goes for the silver leather.
Also a lot of uk cars dont have the alloy mirrors, they were a cost option when new,so not all went for them,also a lot of people had the alloy mirrors stolen and went back to std ones.
Some of the later uk cars came with RS4 style 18in wheels, if they are fitted make sure they are a genuine audi wheel, not replicas, as the quality of the replica wheels leaves a lot to be desired.
A std S3 is ok, great interior( the best in the business) low running costs, well built and a classy very safe and surefooted package, downsides are poor brakes,so so handling and they're not that quick, but all these things can be improved........
