Golf Mk4 1.9 tdi engines and reliability

Hello everyone
my brother imports cars from Germany and I am interested in VW Golf Mk4 TDI. it's not expensive in Germany I can pick up a good one for 800 Euro . (850+350 shipping)=1200 Euro
I'm new here. I read several posts and I still have some questions.
does the turbo on Golf MK4 1.9 TDI has many problems?
which is the most reliable engine (AGR ALH AHF ASV ATD AXR AJM AUY) I don't care about engine power 90ps 101ps 110ps 115ps?
which of these engines are PD (AGR ALH AHF ASV ATD AXR AJM AUY)?
Will I get a lot of troubles if I buy a car with 180K miles?

Since the vehicle you are after is old (10 years?) You will have a lot of variation depending on the type of service life the car had (taxi vs private use ) and also quality service (quality parts performed within the service intervals by quaified mechanic using the correct procedures) ... so, 180k miles on a well serviced car is not terrible otoh 180k on a neglected vehicle will surely have a lot of issues waiting for you. Remember. The previous owners didnt get rid of them because they were performing awesome

Thanks Carlos_TJ

anyone knows which is the most reliable engine (AGR ALH AHF ASV ATD AXR AJM AUY) I don't care about engine power 90ps 101ps 110ps 115ps? and which of these engines are PD (AGR ALH AHF ASV ATD AXR AJM AUY)?

As said before this question has no correct answer. No one can tell how the car was driven or cared for. The engines reliability depends on this. These are all old cars not new cars. A decade or so of use makes a huge difference. This is something to be determined by checking the car out and going over its life/service history.

ALH is the most reliable and bullet proof engine.

I had mine for 12 years and gave it a good run.

I sold my old ALH last year with 230,000 miles on original dual mass clutch (poor bugger who bought it will eventually have to change the clutch out).
It could easily hit 120MPH, on the motorway ...... not any more with the new speed cameras though !!!

I've also got a BKC 1.9TDI with I've owned for 14 years - the clutch hit 220,000 and broke - fixing this at the moment.

Old build quality was a lot better - the old PD diesel engine was in the top 10 rated diesel engines. Simple with less things to go wrong - no oil pump issues etc.

For reliability wise, I'd stick to the PD engines, preferably 1.9TDI's. The newer 2.0TD have oil pump issue, which is a bugger to change out.

Don't buy the non-turbo VW's ....... so so so so sluggish, I could run faster!!!