In reply to goldmember:
If you're thinking of going for a car with the 2.0L Pump Duse (PD) Tdi engine (fitted between 2004-2008), I'd suggest you do some research re. oil pump 6mm hex drive failure. This affects engines with chain driven pump and balancer shaft assemblies in all applications - VW, Skoda, Audi and SEAT. PD engine chain drive oil pump failure can occur at any mileage over 60-70K and a FSH is no guarantee. Not all engines are affected though; it's very much a lottery. If the pump hex drive fails, it'll happen gradually and the engine will run with gradually reducing oil pressure until eventually the drive fails totally. By the time this happens, it's too late and you have a scrap engine. There's loads of stuff about it on VAG forums. VAG will not pick up the bill for a replacement engine even though it's a known engine design fault.
Later engines had a modified gear driven pump, thus avoiding any problems, so the later you go with a PD engine the better they get. But whether you'd then be better off buying a later common-rail injection (CR) engined car will come down to your budget.
A mechanic at a VW-Audi specialist once told me that you can easily see if a PD engine has a chain driven or geared pump by doing a simple dipstick test. The dipstick on a chain driven pump has a slight resistance at the very end of dipstick insertion whereas a gear driven pump does not. I could easily tell the differences by comparing two different engines in the workshop, but I suspect that in isolation it'd be impossible to tell.
Injector failure is an issue with the PD engine too, but at least VAG did a FOC recall and swopped these for modified units. A VIN number check at a Skoda dealer will indicate whether this has been done or not.
The far more reliable 2.0L CR TDi engine was released in 2008, although different VAG models got it at slightly different times - so it'd be worth checking with regards to an Octavia or Superb if buying a 2008/9 model. These engines are supposedly more refined than the earlier PD engines, but IMHO it's unacceptably noisy when fitted in the latest model Octavia. I can't comment whether this is also true for the Superb.
HTH
Dave