I've only just taken a look at this thread so forgive the late input...
The following information is for everyone, and not specifically aimed at Anders - it's just that he quoted what many may be thinking.
I think by the way, that the relatively low price of the pump is affected by the fact that there has been several failures reported of these...
No, it's nothing to do with that Anders. Old type diesel systems used complex and therefore expensive fuel injection pumps that had to be accurately timed, but these new common rail injection pumps are very simple. All they do is increase the pressure from the low supply pressure, to the extremely high common rail pressure (up to 1600 bar - yes that is over 23000 psi !!) There is no need for them to be timed, since all the timing is done by the electronics. Hence they are fairly inexpensive.
Bosch had lots of problems with these, and I think Bosch lost a good deal of money on the common rail diesel systems back around 2000. Then they have probably increased the price of the injectors... the price of those sounds a bit silly.
Again not quite right I'm afraid. The new electronic common rail injectors are highly complex and extremely accurately machined items which have to work at these extreme pressure without leaking externally as well as internally which makes them expensive. Furthermore, owing to mass production, there are still differences between individual injectors which although tiny, is enough that they now have a calibration that the injection computer will use to equalise the power in individual cylinders by altering the fuel amount and/or timing of individual injectors. This is why the injection computer has to be programmed with the injector calibration codes. These codes, by the way, are visible on the injector body, so even if you took an injector from another engine, you can see what code you need to input into the computer. The problem is having the diagnostic equipment to configure the injection computer !
The very latest injectors (not fitted on the Espace) use a piezoelectric crystal stack for opening the injectors so that the response is so quick that they can have up to five openings per revolution instead of the one opening of the old system. One opening gave a harsher engine as all the fuel for that cycle was injected at once. These latest multi-opening systems, injecting smaller amounts in rapid succession give a smoother and quieter operation. However, you can imagine the amount of processing going on to give a tiny pre-injection followed by up to four more small injections all in the space of milli-seconds !
These are the lengths the manufacturers are now going to, to meet emission regulations whilst giving the customers smoother, quieter, yet faster diesel engines. Development is rapid as well as complex, and the garage trade is having even more problems keeping up.
Safety warnings: NEVER open a high pressure joint on these new common rail engines especially whilst the engine is running (danger to you) and never disconnect an injector electrical supply (danger of damage to the engine).