I got my Z from s20004u in November, compared to some other dealers I spoke to they seemed to know a bit about the car and they seemed to have a lot of them go through their books so I thought it all looked good.
I haven't had any problems with the car, it had done 72k when I got it and almost upto 78k now (what can I say I love to drive it!) so i'm sorry to hear of other having bad experiences, looks like I was one of the lucky ones.
I know nothing about cars really, but the thought of a 6 year old car thats done 25k scares me a little, whats it done its whole life other than sit around? Has it only been driven a few miles on weekends like a nutter or to a track and someone thrashed the living daylights out of it? I'm much happier that I got a 'repmobile' thats done 1,000s of motorway miles and been serviced at least twice a year for 6 years because I intend to use it everyday not as a weekend bit of fun. Only thing that bugs me is the millions of stone chips but I can live with that... for now...
They actually gave me a very good trade in, I bought a 55 plate Hyundai Coupe in December 08, put about 10k on the clock, had the front bumper scraped nastily by someone just before I traded it and only lost £250 on it
Its only since meeting a couple of fellow members on here that I realised I got clear front reflectors and newer LED rear lights too ( which is nice )
I guess in the same way you can have the odd bad experience from a good dealer, you can sometimes have a rare good experience from a crap one....