Your putting Peugeot and Reliabilty in the same sentence!?!
If i were you, i would be getting away and moving onto better things than Pugs, but i'm not, so your choice!
2.0 Hdis in the 306 are "ok" but not what they should be as they are only 90bhp examples whilst at the time most manufacturers were having higher output and higher torque for about the same economy. The HDI worth having is the 1.4 - the same one as used in the Fiesta or the 1.6, but that's 206.
Ok, the 1.9D and dT used by PAS were the early standard for decent diesels, they called them the XUD engine basically, and then the DW8 out of memory at the end (non-turbo version only). They are good reliable and strong engines, with "ok" economy. They have "indirect" diesel injection with a turbocharger. You will notice quite a kick from your turbo at around 2.5k RPM.
The 2.0 Hdi however is what is known as "common rail" - a high pressure injection of diesel. They are used as:
Better CO2 emissions
20%+ (typical) better economy over indirect injection
Typically more power (not in the case of the early 2.0 HDIs)
Longer service intervals
Quiter, especially at start up
However, they are complex as common rail needs electrics which can, of course, go wrong. Fortunately, like most common rail engines (and PD, pumpe duse, which is the technology VW preferred for a long time) this complexity has not really decrease reliability. Expect the HDI to have more of a progressive feel from acceleration and less of a 2.5k RPM kick of "old diesels". You can "remap" a common rail engine, but I won't go into that unless you're interested.
Anything else specific, do ask, I know a fair bit about diesel technology and a limited about with regards to PAS diesels (more so on the last version of the XUD which is the DW8 engine, the non-turbo 1.9D).
Ok - the 2.0 306 HDi is supposedly the nuts of a car. What you want is the P3 (phase 3) model, preferrably in Moonstone blue. They look exactly like what is in my profile (although mine is not a HDi). They are well regarded funnily enough, and still have a strong residual price (maybe because it looks like the gti6). It is a bit faster that the D-Turbo and does do more MPG if I'm right.
Gbduo, the 306 diesels have to be some of the most reliable cars ever manufactured, I looked at buying one but they simply all have 150K+ on them no matter how old (typically 200k+) and the low mileage examples demand premiums that mean they are not worth it IMO for the overall package. Ask anybody in the motortrade and they WILL say similar.
I am proved wrong by my peers...again!
I concede my point!
I was looking at the 3dr for the looks, the only thing that puts me off is the price, (not many in good condition with a decent mileage (trade or private) for under £3k where i live)
At the moment i have a 5dr 1.9TD which is going on 100k (ive had since 94k) and ive had no problems with the car apart from a minor oil leak..
In the final phase is there much change to the interior/equipment over the original?