I didn't mean to come across as scaremongering, just giving my opinion and also my experience.
You PMd me about your car, and I seem to remember you worrying more than just discs and quite a few other components that needed sorting. But I wont go into details on here.
Mine wasnt 2k more AUC, they dealt well in the end and got a car that I didn't need to do anything to in theory until its next service in 2 years time, if not the warranty is there to fall back on. Also you get the full BMW inspection which gives you comeback if its not right as an AUC car, and obs the warranty which was worth its weight in gold for me, as im not savvy mechanically.
People who say that warranties aren't worth having obv haven't had any problems with their cars, fair, until you do then you might think twice which is why I got 2 years, covers me for the minimum amount of time I will keep the car. The reason mine needed work doing was because it had a fault which could happen to any car, mine was a fairly rare one that ended up having to have the ECU replaced and quite a few other electronic components that were difficult to diagnose. But it was £1400!! that mostly the labour costs, now if that had happended to you after you had just bought your car privately you would be pretty pissed? and it would probably take the shine off, and if you add that £1400 to say the 14k car for sale your looking at £15.5 not looking so cheap now. But that is my experience, so I will stick to it.
Also with Stus Alpina, his had a lot of warranty work done to it similar to mine, and the warranty paid for itself with one visit. These faults are not things you can plan for, but I no that me and Stu are quite Anal and the car has to be like it was when it was new or it wont do. Hence why he has just bought that lovely queen. These cars arent getting any younger and the oldest being 7 years, its getting on in car years, much more likely for things to go wrong you wouldn't expect, bushes, sus, seals, most likely culprit being electronic etc etc
The thing is if you buy from a dealer you at least have some come back, if you buy privately you cant go back to the owner and be like well its broken. Similar to my Ebay thread, buying something in good nick and breaking it. It could have been bad luck it could have been malicious. Either way you will end up with the bill for sorting it.
Again you can have great experience, but im always wary because they will always tell you its the best car since sliced bread, until 6 months later.
But again this is my experience. Just have to be careful buying privately thats the point I was making.
I actually had a torrid time with BMW, it was poor and well documented on my thread. But that was my dealer and there are many examples of poor service on here. I had comeback and had everything done without me spending any more, at the end of the day my car was sorted with the only thing detrimental to me being without the car for 2 weeks.